For the last 12 or so years I have varnished (the SPAR/UV resistant type)
all my hive parts. I usually let them dry out in the sun for at least a
month before putting them anywhere near the bees. Probably because it
impregnates the wood I dont loose much if any when I set to work to scrape
the propolis off.
Doug. Cutler Office of Information Technology,
VM Systems Programmer University of North Carolina.