On some of my older DVDs, there is some kind of odd trace around the edge of the disc... you can see it in the image where the light is reflected. I can wipe it off, but it's really sticky and takes some time to clean up. More sticky residue is all over the disc, so the trace only seems to be some accumulation of stuff that's all over the bottom side. Best thing that worked so far was soap and water and a bit of patience. Any idea what this is and how to prevent this for my other discs? Or is it a known issue for some weird kind of disc? Discs obviously don't work until they are cleaned.
In their boxes, some in the basement, others in the living room
So far, I have seen this on Star Trek DVDs. Odd thing here: it's both, on a set of tng DVDs that I had bought new about 15 years ago and a set of Voyager DVDs that I had recently acquired used. So I just guess it's not related to my house, because of those third party used ones.
Not sure, but I guess so.
If memory serves, TOS, TNG and DS9 were initially released on DVD in hard plastic collector's cases (one per season) and spaced over a few years (don't remembering seeing VOY get this treatment). A few years later TNG, DS9 and VOY got a re-release in slimline DVD cases, with each season consisting of 4 packaged in a cardboard slipcase/box. Here in Australia, at least, each of the three series had limited-edition carry cases if you bought all 7 seasons together. There have been several other re-pressings since.
If your DVDs are all matching (e.g. from the same release run), then I'd be suspicious that it's the discs themselves or the cases (but you've said elsewhere it's not the cases, so...). Obviously it's an utter pain to back up that many discs -- 46 to 48 for each series, depending on which release you've got. If they're notably different pressings, though, then I'd think it less likely to be the discs themselves.