Short answer - yes.
Mud and water won't harm the actual tape - best option is to dis-assemble the tape and remove the spools from the casing. Carefully rinse then in clean water - DON'T let the tape come off the spool!
Place the wet spools in a dry warm place for AT LEAST a week.
Clean the casing - or (better) sacrifice another tape replace the tape spools with the dried-out ones.
Insert tape into your VCR but DO NOT allow it to play. Wind the tape about half way through. Remove it and examine the tape. If there is the slightest sign of moisture, give it another week in the warm dry place. If not, wind it to the end and check again. If still no moisture, tape should be safe to play - but I suggest use a cheap-to-replace VCR at least to test it.
Copy the tape (preferably to DVD), then BIN the original. There may be grit embedded in the tape which will not do your VCR any good at all.
phil_saunders@bigfoot.com
Phil Saunders, June 2008