Selling a catalytic converter in California
California has detailed converter-specific law. A buyer of individual used converters is a "core recycler" with its own record, payment, and retention duties under the Business and Professions Code, and the Vehicle Code separately fixes the short list of people a used converter may be bought from at all.
Last checked September 13, 2026; source material current as of November 11, 2025. Laws change. Confirm the current statute and its effective date before relying on this page. This is not legal advice.
Who may sell a detached converter
No person may purchase a used catalytic converter, including for dismantling, recycling, or smelting, except from a licensed automobile dismantler, a core recycler with a fixed place of business that obtained the unit under § 21610 of the Business and Professions Code, a licensed motor vehicle manufacturer, dealer, or lessor-retailer, a licensed automotive repair dealer, or any other licensed business that may reasonably generate, possess, or sell used converters (Veh. Code § 10852.5(a)(1) to (5)). A private individual is the sixth route: that person has to hold documentation of lawful ownership, such as a certificate of title or registration naming them as legal or registered owner of the vehicle the converter came off, carrying a vehicle identification number that matches the number permanently marked on the converter (Veh. Code § 10852.5(a)(6)).
Two definitions do the work. Permanently marked means prominently engraved, etched, welded, metal stamped, acid marked, or otherwise permanently displayed by a similarly reliable lasting method on the exterior case (Veh. Code § 10852.5(b)(1)). A used catalytic converter is one previously installed on a vehicle and since detached, and does not include a reconditioned or refurbished unit sold at retail (Veh. Code § 10852.5(b)(2)). The Business and Professions Code uses a parallel term, commercial enterprise, covering licensed dismantlers, core recyclers with a fixed place of business, licensed vehicle manufacturers, dealers and lessor-retailers, licensed automotive repair dealers, and any other licensed business that may reasonably generate, possess, or sell converters (§ 21610(a)(2)).
A core recycler is a person or business, a recycler or junk dealer included, that buys used individual converters, transmissions, or other parts previously removed from a vehicle; buying a whole vehicle that may contain those parts does not make you one (§ 21610(a)(1)). The section's duties apply to core recyclers and not to a later purchaser who is not one (§ 21610(l)). Violating the Vehicle Code list is an infraction punishable by a fine of one thousand dollars for a first offense, two thousand for a second, and four thousand for a third or later one (Veh. Code § 10852.5(c)).
What the buyer must record
Every junk dealer and recycler keeps a written record of all sales and purchases made in the course of business (§ 21605(a)), setting out the place, date, time, and amount paid for each transaction and the name of the employee who handled it, one of the permitted forms of identification, the plate number and state of issue of any vehicle used to bring the junk in, the name and address of anyone junk is sold to, a description of each item including type, weight, engraved or etched marks that are readily visible, and readily visible serial numbers, and a signed statement that the seller owns the junk or naming the person the seller got it from as shown on a signed transfer document (§ 21606(a)(1) to (6)). Identification is a name with a driver license or state or federal identification card number, or a passport or Matricula Consular number with an additional item bearing the seller's name and address (§ 21606(a)(2)). That information is reported to the chief of police or the sheriff in the manner § 21628 sets out (§ 21606(c)), and the written record is preserved for at least two years after the final entry (§ 21607).
A core recycler accepting a converter keeps a separate written record: the place and date of each sale or purchase, the seller's name, valid driver license number and state of issue or California identification number, and the plate and state of the vehicle used to bring it in, with a commercial enterprise instead giving its name, physical business address, business telephone number, and business license or tax identification number (§ 21610(b)(1), (2)). The record describes the converters by item type and quantity, the amount paid, any identification number, and the year, make, model, and vehicle identification number of the vehicle each came off (§ 21610(b)(3)). It carries a statement that the seller owns the unit or names the person the seller got it from as shown on a signed transfer document, and, where it applies, a copy of the title showing the vehicle identification number matches the number permanently marked on the converter (§ 21610(b)(4), (5)).
Selling on is recorded too: a core recycler shipping or selling used converters to other recyclers or smelters retains the name and address of each buyer, the quantity, the amount paid, and the date (§ 21610(c)). All of it is kept for not less than two years and made available for inspection by local law enforcement on demand (§ 21610(g), (h)). Two narrower paths exist for standing commercial relationships. Where a core recycler holds a written agreement with a commercial enterprise, it need collect only the seller's name or agent, business address and telephone number, business license or tax identification number, the transaction date, the number of converters, the amount paid, and a copy of the agreement (§ 21610(f)); the agreement has to include a log describing each converter received with enough particularity, identification numbers and markings included, that inventory can be matched back to it (§ 21610(e)).
How you are paid
Cash is out for converters. A core recycler may not pay for a converter unless payment is by check, credit card, or another traceable form of payment other than cash, and it either goes in the mail to the seller at the address supplied with the identification, or to a commercial enterprise's business address, or is collected by the seller from the recycler on the third business day after the sale (§ 21610(d)(1)). A commercial enterprise is the exception on timing: it may receive immediate payment by check, debit card, or credit card (§ 21610(d)(1)(B)(ii)).
Four things have to be in hand before payment is made. The core recycler takes a clear photograph or video of the seller, obtains a copy of the seller's or the agent's driver license or government-issued photo identification card bearing a photograph and address, takes a clear photograph or video of the converter that captures the permanent vehicle identification marking where there is one, and obtains a written statement from the seller saying how the converter was obtained (§ 21610(d)(2) to (5)). The seller also has to be one of the people Vehicle Code § 10852.5 allows (§ 21610(d)(6)). Where the seller wants payment mailed to an address other than the one on the identification, and not a post office box, the recycler also takes a gas or electric utility bill addressed to the seller there with a due date no more than two months before the sale (§ 21610(d)(3)(B)).
The three-business-day rule is a payment timing rule, not a hold on the metal. California's separate hold power sits with law enforcement: where a peace officer has probable cause to believe property held by a junk dealer or recycler is stolen, the officer may, instead of seizing it, place a written hold on it for up to ninety days, during which the dealer may not release or dispose of it except under a court order or a written authorization signed by a peace officer from the same agency (§ 21609(a)). For general nonferrous material, meaning copper, copper alloys, stainless steel, or aluminum, a parallel payment regime applies with cash permitted but collection deferred to the third business day, together with photographs, identification, and a thumbprint kept two years (§ 21608.5(a), (h)).
Penalties
The converter section carries both a general misdemeanor and a fine ladder. Making or causing to be made a false or fictitious statement about any information § 21610 requires is a misdemeanor, and violating the section's requirements is a misdemeanor (§ 21610(i), (j)). On conviction for a knowing and willful violation the fine is one thousand dollars for a first offense and not less than two thousand dollars for a second, and the court may additionally order the defendant to stop doing business as a core recycler for up to thirty days (§ 21610(k)(1), (2)).
A third and subsequent conviction carries a fine of not less than four thousand dollars, and there the court has to order the defendant to cease business as a core recycler for at least one year (§ 21610(k)(3)). Those consequences fall on the buyer, so a shop or yard selling into a California core recycler will find the recycler unwilling to complete a transaction that is missing the title match, the ownership statement, or the identification the section requires.
On the general junk and recycler side, making or causing to be made a false or fictitious statement about anything § 21606 requires is a misdemeanor (§ 21606(b)). Buying a used converter from someone outside the Vehicle Code list is an infraction with fines that climb from one thousand to four thousand dollars across three offenses (Veh. Code § 10852.5(c)), and a peace officer's ninety-day hold under § 21609 keeps a suspect unit in place while ownership is worked out (§ 21609(a)).
What this means when you sell to us
Bring a government photo ID with an address on it, and the title or registration for the vehicle each converter came off where you are selling as an individual, so the identification number on the paperwork matches the number marked on the unit (Veh. Code § 10852.5(a)(6)). Businesses bring the business license or tax identification number instead. You sign a written statement of how you obtained each converter, and we photograph you and each unit (§ 21610(b), (d)). Cash is not permitted. California requires a check or another traceable form of payment, mailed to you or collected on the third business day after the sale, with businesses paid immediately (§ 21610(d)(1)).
