I just though id share this. I bought a Fender USA Jazz bass from ebay a few weeks ago, but the poly finish was damaged where the strap button attaches on the top horn. It looked pretty bad so I thought id have ago at a repair. To cut a long story short i filled the hole with P38 car filler and sanded it with 1000 grit wet and dry. After getting the shape correct i painted it with black nail varnish. I gave it 4 coats gently sanding it with fine wet and dry between coats. After leaving it another 24 hours to dry I polished it with T cut. Its not perfect but a lot better then it was.
http://www.switchmusicsupplies.co.uk/ 