Use car polish and buff it up with that. Works wonders on removing scratches.
Failing that, get some Displex (eBay). I had a disc somebody sandpapered/knifed and wouldn't even recognise. After a quick go with that, the whole CD played through with no skips / jumps
You can legally make one copy of every game you own, but you'll have to chip your PS2 to get the copy to play.
For copying guides, see the Ultimate Info Sticky at the top of the forum