What's with the clear fuzzy stuff

[LeviT]

It looks like the skeleton of this hammer has a thick film on it. Has anyone seen this before? You can tell best on the right side. I was going to scrub it off but thought I'd pick your brains first.

Sorry, I tried to get a close pic but this is the clearest I could get.

 

[Gomer]

reminds me of the fungus that grows on new wood placed in a freshwater tank.

 

[Raddogz]

Sponge would be near best guess