Subject: What are possible reactions between formic acid and PMMA?

I recently found that formic acid will actually eat holes in thin films of 
PMMA. This resulted in a pitted PMMA surface everywhere there had been a drop 
of formic acid.  I know formic acid is a solvent for PMMA, but how could the 
PMMA be cut into pieces small enough to be evaporated?  There is a possibility 
of the formic acid inserting itself at the oxygen attached methyl group but how 
would that create the observed pits?  Any advice or direction as to where I 
should look would be much appreciated.  I guess an answer would be good too.

Re: What are possible reactions between formic acid and PMMA?