is it safe to clean records with isopropanol ?

"I can say I have had no issues, but how would one know, unless the damage was rapid and gross?" True...and I agree with you, Lew. The way I see it, as an approximately 70 year old fart, my hearing is a fair cry from what it used to be, though I'm still enjoying what I AM hearing, and as long as that's so, I'm good. Best wishes with the hope you're enjoying the music too!

So what does isopropyl alcohol do that a mild soap / detergent solution doesn't? When I want to remove grease, dirt, slime, residues and other contaminants, I use soap and water and rinse with clean water. What does alcohol do better.

I started to clean stubborn dirty LPs with a 9.6 % ammonia solution. A bit inconvenient to apply so a careful procedure is required, but the cleaning results are amazing.

I put it directly on the vinyl, brush the discs for about five minutes, then vacuum it off. Final cleaning with my standard solution, vacuuming, and that's it.

Reduction off crackle could be dramatic.

"So what does isopropyl alcohol do that a mild soap / detergent solution doesn't? When I want to remove grease, dirt, slime, residues and other contaminants, I use soap and water and rinse with clean water. What does alcohol do better?"

That's a very good question Bpoletti-the answer to which, I believe, is nothing.

I keep a bit of isopropyl around and might use it to clean maybe one in maybe 50 or 60 records at most, mainly those that have something very sticky on them. Apart from that, my view on isopropyl is that it is simply not very good at cleaning records and doesn't contribute much to the process at all. It is not a very effective cleaning agent.

There's quite a bit of difference between what alcohols do and what mild detergents do, and fortunately for us, the thread that best described the differential effects of the various potential components of a record cleaning solution seems to be "alive" again. Look down the Analog Discussion page and find the thread on record cleaning solutions. The first post is a very useful summary of good research on the subject by a guy who obviously knows some chemistry.