There are several paint stores, like Dunn Edwards and Sherwin Williams that are part of the paint recycling program. They will take your old paints.
City of San Diego accepts old paint at the Hazardous Material Office, located at the Miramar Landfill next Alan Recycling. However they will only accept paints by appointment only. You need to call the customer service number. Go to the web and type in Environmental Services to get phone #, you might be able to schedule online too..
Thanks! Your answer is awaiting moderation.