Instead of focusing AI piloted cars, maybe we should build AI piloted boats to collect plastic from oceans.

Put sails on them to assist. And solar panels. Nets. The plastic doesn't necesarrily have to be brought to shore but concentrated to safer waters, or perhaps burnt on site, using it as fuel, and have the smoke filtered if necessary. Maybe use high temperatures, hoping it'll burn cleaner. Or have the plastic waste packed into tight cubes, decreasing the plastic's contact surface area with water. Or seal the plastic inside more resistant material, bags or barrels that don't easily decompose. We could consider packing and concentrating the plastic to one area and then nuke it all.