boat hull plug tricks?

hey guys, im getting the boat ready for winter and that got me thinking
is there a trick to getting the hull plug out?

(no i wont remove it for when i hit the lakes)




it seems like its is frozen in there

now, its just a brass plug in a brass "nut"

i dont want to really reef on it, since i dont want to rip the mounting screws out of the hull
and since the boat is fiberglass, i dont know is getting it really hot is a good idea either

for now, ive been soaking it with WD-40 (i know, i need to get some PB blaster or something)

now, im thinking pulling the 3 mounting screws, and replacing the whole thing, but i dont know that the best way is to seal it up again