If you are daring, make good friends with a hobbyist telescope maker and give it a go.
Yup, glass pusher here, but a long time ago. You need to make a pitch lap and try cerium oxide as a polishing agent. You mold the soft pitch with the lens itself thus perserving it's radius. The finer marks should polish out, the deeper gouges won't. Of course the lens element has to be removed to work it on the lap. The trouble is getting only small amounts of the materials you need.
One can buy small amounts of diamond lapping/polishing compound, pretty reasonably, from McMaster-Carr.