Thanks for the advice!  I am planning on going
back and replacing the mat board (it got pretty
damaged when we removed it last night).  

As for removing the goo, I used the clear nail
polish remover, which, as of this morning, appears
to have worked marvelously (don't see any
discoloration to the cel whatsover, except for
that nasty tear, *grrr*).  But, I also used a q
tip to rub only the goo part and didn't directly
touch the cel with the chemical.  Just an FYI for
others who do stupid things like me!  :-)