Spent the evening going through most of the Japanese pressed cardboard thin package CD's that would have a plastic CD sleeve for the disc, and there's a lot of it in my CD collection.
Thank goodness the only damage was a couple of Pink Floyd Discovery discs that I'd probably buy replacements for the damaged ones to make the set complete.
Tried all means to clean the plastic smears from the surface of the disc, but the smears seems to be bonded into the plastic of the disc. I will continue to experiment with various cleaning agents.
Surprisingly, the earlier Japanese cardboard sleeve packaging (late 90's to early 2000) that also had plastic sleeves DID not caused any smearing of the CD's. I'd not take the risk, will replace with the cloth sleeves.

I still gave 14 packs of the plastic sleeves, and they did not come cheap...bummer

Also, if you have any video discs stored is a softer bendable plastic packaging (mainly Blurays), do check the condition of the discs over time.
A box set of "I Love Lucy" that was packaged in ultra thin bendable plastic DVD was all smeared with the melted plastic that reacted with the discs.
In summary, any packaging material that can crack or tear easily - hard shell plastic or paper is OK, any plastic that requires some force to tear or rip if apart will damage your discs over time.Then again, like RD has commented, hot humid climates is probably the most likely cause of the problem.