I wouldn't worry too much about the outside...looks mostly like staining.
The fuzzy stuff on the inside, might try vacuuming it off(shop vac with bristle brush attachment) then wiping with a mild bleach or vinegar solution...just to keep it in check until things get dry enough to paint.
You might have to set some thing up for birds for a couple days while paint/whitewash dries.
The fuzzy stuff on the inside, might try vacuuming it off(shop vac with bristle brush attachment) then wiping with a mild bleach or vinegar solution...just to keep it in check until things get dry enough to paint.
You might have to set some thing up for birds for a couple days while paint/whitewash dries.