Wondering if any of you can help me identify a white filmy/powdery
substance on the pack of an open reel tape. At first glance it looks like
mold but on closer inspection it isn't. There is some kind of chemical
breakdown happening obviously and the tape is polyester with
back treatment. The tape is TDK GX 35/180Bm. There are other tapes in the
same collection with the same condition but not sure of the brands as they
are in generic boxes. The only thing in common is that they all are back
coated.

Any information on what this is and how to get rid of it will
be appreciated.

-- 
Jonathan