My worst ever rip on my Macbook Pro's internal drive was on a very damaged copy of The Sisters Of Mercy, Floodland. The disc looks like it got taken on a trip to the beach and thrown on the floor of the car on the way back. It's not destroyed, but it's extremely scratched over most of it's surface in circles and swirls.
I think I spent about 1.25 to 1.5 hours on that disk across two different ripping sessions. I eventually got a totally clean rip audibly: No clicks, no pops, no beeps or boops. But only a small number of the tracks were ripped "perfectly". The others had errors, just not audible.
A few other discs I've done similar things with, most taking 30 to 45 minutes of total rip time. At least 2 or 3 of those have required a re-rip of one or two songs because the songs had audible clicks or pops in them. This process is SUPER tedious because you have to listen to every second of every song to be sure. I'd REALLY rather buy discs that are in good shape these days, but occasionally I get a stinker.
I've taken to actually WASHING ugly discs first now. With dish soap and water, using my fingers to apply it. This actually helps in some cases. I've also tried toothpaste as a mild buffing compound, using mostly straight lines from center hub to disc edge. I've had just about zero luck doing that and have introduced fine scratches in a few discs doing this too. Ooops. There are disc resurfacing machines starting below $100 for "ok" models and going up to around $400-ish for more professional models that are supposed to do an amazing job. You might get lucky and find a local store that rents games or DVDs that actually has one of these machines that might resurface your discs for a small charge per disc.
Good luck on your mission Sergeant Ferday!
Brian.