Drive a personal vehicle to Los Santos Customs
Enter the shop and select Sell
Confirm the sale price
Wait for the cooldown before selling another car
Use only cars that can be sold
Avoid selling stolen high-end cars if they are not eligible
Check the daily sell limit to avoid restrictions
In GTA Online, sell cars from your own garage or the street if allowed
In Story Mode, sell cars only at Los Santos Customs
Keep in mind that some mission vehicles cannot be sold