Hi Anvil, 

surprised nobody responded.....i guess its a bit depressing.  the following is from systemthree website:

Resin (Part A) can actually be cleaned up with white vinegar, as can some hardeners (Part B).  But solvents such as lacquer thinner, denatured alcohol, and acetone will be the best choice for cleaning up any mixed uncured epoxy. 

i have had this problem once a while ago with MAS and it was basically the same advice.  first, however, do remove as much as possible with a plastic putty knife (being careful not to scratch the panels).  MAS has the following video on the topic: https://www.youtube.com/watch?v=S_pz_6lVlbY

h

This happened to me as well so you're not alone! Mine occurred during the third coat of epoxy after fiberglassing, so I only needed to take it back to the next coat. Since it sounds like yours is during the first coat on bare wood, the uncured epoxy may have soaked into the wood and thus will be more difficult, or impossible, to clean off. The below was my process. Your mileage may vary in your circumstance.

I scraped off the goo as best I could with a paint scraper then wiped/scrubbed with a scotch bright pad and then a cloth with a generous amount of denatured alcohol. It took some work but I got to a point where everything was sicky-free and reapplied the epoxy. 

Ed,

This happened once when we were glassing our Peeler Skiff. It was a real pain to clean up (with acetone), but caused no lasting damage.

We attributed it to a failure to properly mix a batch of MAS resin and hardener. We became much more careful and it has never happened again.

Cheers,

-Dick-