I've embarked on an ongoing effort to get my vinyl digitized, and I've learned rather a lot about how best to do it...and I'm posting my findings here because (a.) it's nice to have new stuff up here every now and again, and (b.) I'd like to hear more advice if anyone's willing to share it.
Firstly, I've discovered that some of the things you'd think would cause problems actually don't. Visible scratches on a record don't necessarily translate to audible noise. That's because the scratches you see on records generally only affect the top part of the groove, and when your record needle plays what's in you're groove, it's actually nestled deeper inside it than the surface blemishes can reach. (Big scratches that reach deep down into grooves can still make noise happen, of course.)
So what makes most of the pops and clicks you hear when you play a record?
Dirt. Dirt clings to the inside of grooves - the part the needle actually plays - and makes your needle do things that it shouldn't.
So what do you do about dirt? The solution I've heard about that seems to work for me is to wash it out. I fill a spray bottle with three parts filtered water, one part alcohol (91% denatured - check the label) and a couple of drops of the right dishwashing detergent (Dawn, basic, with no additives.)
Using this stuff, I've cleaned off records I used in clubs in the 80's, and I don't know what's been stuck to them all this time, but after it comes off it's kind of a grayish-yellow. (Ew...and to think you were listening
to that.) After cleaning, not only do they sound better, they look better.
Set the record on a dust-free cloth (microfiber cloths are good for this - if it's good enough to keep a Porsche's finish shiny, it'll do the same for your records.) Spray on, use another microfiber cloth to dry off the label, and let it sit about a minute. (If you can avoid the label entirely, even better.) Then gently wipe it off.
I also use the water/alcohol/Dawn solution on the edge of a Discwasher record brush
soon afterward and give the record a gentle but thorough scrub for about 10 rotations on the turntable, which does a good job further removing the softened-up gunk in the grooves. Then I use a cloth to dry out the record brush so that I can use it to dry off the vinyl.
Don't play the record while wet, though, unless this is a hail-mary digitizing pass and you never plan to play the record again. You'll actually get pretty good digitizing results as the needle pulverizes the soft gunk in the groove, but the end result is that the passing needle turns the wet dirt into wet microsludge that deposits further into the groove, and you'll never get it out after that; it winds up a bit like microscopic cement.
For digitizing, I use the latest Audacity
version (which is technically a "beta", but which I've found to be quite stable.) It has a "repair" feature that does a good job of restoring the waveform that should replace individually-selected pops and clicks, but you have to find and select each pop manually. I wish it would go through the music you've digitized and say "this looks like a pop; do you want to repair it?" but I guess that's better left saved for a future version. I used to use the "noise reduction" feature, but I find it removes more of the actual sound you're looking to keep than I'm comfortable with, so I now just remove the more egregious pops and clicks using "repair".
Thus, I'll keep on digitizing, and you'll reap the benefit listening at altrokradio.com...