replying to Leftfeilder, AC me wrote:
When I try to remove it; it smears. I've never had this problem before.
tg
My units from the 1990s started doing that a few years ago. Blowing sheet-like
chunks of smearable stuff that has no mold odor to it, as well as finer
particles. I'm sure its not mold (I hope) because I am allergic to mold and I
always feel better - breathe better - with the units running. I took the front
off - the face bringing the grill mount with it - and cleaned what I can get
to, but it makes no difference in the debris production, especially at first
use after the heating season. I clean the dust filters once a week when I'm
running the units. They sit in the windows over the winter as I can't heft
them out anymore and have no place to put them if I could. They work well - my
hunch they are better than anything I could replace them with. One is made in
the US and the other in Japan.

--
for full context, visit https://www.homeownershub.com/mainte...rt-446601-.htm