Pictures would be helpful. Fungi? Dried cornmeal? What have you been feeding lately that you haven't been before? or anything new added to or included into the bedding materials?

Yes, it's very hard to tell without a picture. Sounds like it could be some kind of fungus? Have you been putting in anything woody?

Bedding is always the same but I do and have fed a mix of cornmeal and oats every once in a while. Anyway heres a couple shots of the stuff .

Very odd. My guess is some sort of mold, mildew, or fungus. Could it be that some condensation forms on those areas at certain times, maybe at night when you're not looking? Does the stuff wipe off easily? I'd maybe try wiping it off a sponge or cloth using some vinegar and water solution (very carefully so as not to get any in the worm's living area.) Hopefully it doesn't need serious scouring.

It could also be some residue from minerals in the moisture from the bin. If that were the case, then a vinegar solution should dissolve it.

Are these indoor bins?

Yes, looks like mold to me too... or perhaps mineral deposits but I just don't see mineral laden water wicking upwards on a plastic surface without some kind of capillary action to provide for the upward movement. I'll go along with the "condensation forming" hypothesis causing mold growth. Mold generally will not form on new polyethylene but after exposure to UV and/or heat and air for awhile (months or years) the surface will begin to oxidize and mold can gain a foothold if the moisture is present and persistent enough. (If its a styrenic plastic then mold can form much sooner... how to tell the difference? If the plastic floats then its polyethylene or polypropylene otherwise it either ABS or PVC which I highly doubt it is).

Looks like a pattern of scratch or scrape marks in the white substance on the bottom picture. Are they old scratches in the plastic, or new marks made by attempts to clean off the white stuff? If the plastic is scratched (understandable events in the life of a worm bin) the rough surface might allow for...something....to collect or take hold.

The stuff was a bit thick and the scratchy marks are where I smeared the stuff not really scratches. I took the bins out and the stuff washes off easily so Im guessing its the cornmeal mix, no more cornmeal for a while.

The stuff on the blue bin simply looks like bird droppings residue to me... Like maybe a local bluejay or a chicken hopped up there was looking for a free lunch in your bins.... or climbing out of them? Maybe an escapee, or some other kind of bug climbing in or out....

The red bin is a bit more difficult, more of a mystery, because there, it still looks like droppings, but like they have been rubbed/smeared onto the bin between the two ledges.... What does that?