This is easily the worst case I've seen so far. In the Thundercats DVD set I bought back in 2009, which has 24 discs,
eight of them have out-gassed a sticky residue all over the data side. You may ask, "But how sticky can it be?"
Also, it's not just an even layer; there's an outer ring of raises beads that look like the disc is sweating.
Curiously, that ring is as far out as the stickiness goes; the very outer edge is still normal. The disc cases have corresponding greasy patches that match this area, but that's not sticky, and the rest of the case surface is fine. So unless I'm missing something, it's probably the discs causing the problem in this instance, not the cases. Also, these are Warner Bros discs from the late 00s, so that's the main red flag for it being the discs themselves.
The glue-like consistency means I couldn't dry-wipe it off, so I did some research and tried experimenting. This page looked like a reliable source, since it's from the Council on Library and Information Resources:
6. Cleaning
I tried Zeiss lens wipes first, but they were useless for this. They didn't get the residue off and just left bits of paper stuck to the disc. What ended up working was a few drops of pure isopropyl on a micro-fibre cloth. Even the beads of liquefied plastic wiped off easily with that. Bear in mind these are DVDs though, so I don't know how well that would work for other types of discs.
That said, it's probably just a temporary fix if it is the discs themselves that are deteriorating due to WB's shoddy manufacturing in the 00s. With nothing to indicate that it's the cases instead, just swapping those out probably wouldn't do any good. I'm considering buying a whole new set. The one currently listed on Amazon has different packaging from the one I bought in 2009, so the discs will hopefully be a lot newer.
I hate having to deal with shoddy quality control like this. I've been stressed all month due to various aggravating things I won't get into, and watching 80s cartoons is usually my last line of defence. Now even those are out to annoy me.
