I must admit - I've never been one for thrifting. Still, somehow a few years ago, my girlfriend managed to get me into it. I can safely say it is now one of my favorite pastimes; finding something is fantastic, and even a fruitless search can be great fun.
When it comes to my items of choice, I prefer to go with unique electronics, computers, CDs, and books or magazines - and I've managed to develop a certain set of "procedures" when it comes to cleaning, restoring, and organizing said items, which I hoep to share with you, dear reader.
When it comes to optical media, for me, cleaning / restoration consists of three parts - the outer box / jewel case, the print material (cover, and booklet), and the actual disc itself. While resurfacing discs is a fantastic hobby that returns old, worn CDs to former glory, I'll go into that another time.
For now, I'll just go into the quickest way to go from the CDs you just picked up from the thrift store, to CDs that are ready to enter your collection.
The first thing I do, of course, is go over the case with a disinfecting rag. For the CD, I like to use isopropyl alcohol; it can damage printed CDs though, so opt for a CD cleaner if you are hesitant.
One of the biggest annoyances is the awful adhesive used on the stickers at the thrift store; the price tags are perforated in such a manner that they cannot be swapped without leaving residue. While I cannot say for certain, I presume this may be an anti-tampering measure.
Removing the sticker needs to be done gently, while preventing tearing / sticking as much as possible. A firm but careful peeling method is necessary to prevent the sticker from ripping. If you've accidentally begun tearing it, approach from a different side, and try to "pick up" the torn edge.
Personally, I have two ways of addressing leftover residue - while you could use a commercial product like Goo Gone, I like to use either 99% isopropyl alcohol, or baking soda with olive oil. Both are fantastic for dissolving or scrubbing away residue without damaging or scratching the case.
For broken jewel cases, I like to "cannibalize" the cases from CDs I enjoy less. After swapping all material and the discs themselves, I'll tuck the less-loved disks into the back of my collection.
When it comes to repairing jewel cases, I'll fix broken hinges with superglue (and a sprinkle of baking soda as accelerant / filler), and I'll use the same glue to fill cracks, to prevent them from getting worse.
They don't manufacture these cases as much as they used to, so I will say this - take care of them! That plastic only gets more brittle with time, which necessitates gentle handling, and prompt repair.
Considering the sensitivity of electronics to liquids, one ought to treat them as if they were made of paper. While the externals can be wiped down without issue - after all, you'll be dealing with metal, plastic, or, with vintage radios and speakers, wood.
For the internals, you will want to remove years, and possibly decades of dust, gunk, and various other debris - I have an air compressor for this, which works incredibly well to remove most contamination.
A slightly riskier "tool" to use is isopropyl alcohol - the higher purity, the better, as it tends to not damage electronics. While I wouldn't recommend anyone to do this, I did successfuly save an SSD that fell in mud, by washing it through with 99% isopropyl alcohol, and blowing it with an air compressor, over the course of a few hours. Needless to say, after moving all my data off it, I didn't reuse it. I've also learnt the value of backing up every other day.
Arm yourself with a variety of swabs, brushes, and dry wipes / microfiber cloths. All of this can be purchased at a dollar store, so don't waste your money buying "brand name". My microfiber towels have lasted me for years, and cost about $2.00 for 3.