I have a Athalon 1800+ standard heatsink and have to get a new motherboard. I have a question.

1. Should I remove the goo from the heatsink?
2. Should I remove any of the goo from around the actual chip?? It looks like it's on the side of the chip (melted). I tried this once before and it just got worse!
3. If I do have to remove the goo and re-apply thermo paste what should I use to remove the goo ?? I used nail polish remover, but it took forever to get it off.

Thanks in advance.