Guides — buying used auto parts

Short, current answers to the legal and practical questions buyers ask before paying for a salvage car or used part. Each guide leads with the answer.

• What do part grades A, B, and C mean?
  Salvage part grades A, B, and C signal condition and expected life. Grade A is tested and low-mileage; B is functional with wear; C is sold for repair or rebuild.
• Salvage vs rebuilt vs clean vs junk title — what's the difference?
  Clean titles have no damage history. Salvage titles mark a vehicle declared a total loss. Rebuilt titles mean a salvage car was repaired and inspected. Junk titles mean parts-only, no road use.
• Is it legal to buy a used catalytic converter? State laws as of 2026.
  Buying a used catalytic converter is legal under federal law if it is EPA- or CARB-certified for the vehicle. Several states require seller documentation, ID, and proof of vehicle ownership.
• Is it legal to buy a used airbag?
  Buying and selling used airbags is legal in most states, but installer liability is severe and several states (CA, NY, MD) restrict or ban resale. NHTSA strongly discourages used airbag installation.
• How do I verify a VIN matches the title before buying?
  Compare the VIN on the title to the dash plate, driver-side door jamb sticker, and engine block. Use the free NHTSA VIN decoder to confirm year, make, model, and engine match.
• How do I buy a used EV battery pack safely?
  Used EV battery packs carry 200–800V hazards. Buy only from sellers who can document state-of-health, do not disassemble undamaged packs, and verify the carrier accepts lithium-ion freight under 49 CFR 173.185.