Not just rodents. Many years ago in a 1-26 contest in the U.S., one
poor pilot flew several days barely able to tolerate the smell from a
dead bird somewhere in one wing. I'm not sure how he removed it but I
seem to recall that part of the solution (no pun intended) was to
partially fill the wing with water from the root rib, slosh it around,
then stand the wing up on the tip of the spar and pour it out.

Chip Bearden
ASW 24 "JB"e