Hi Jack.

Being a fiddler I was attracted to this page 'coz I thought it said

"banjo tuners vs. wooden stakes" :-)

However, I'd second the above suggestion to use violin methods first. That presumably works in the wild.
But don't use homespun remedies like chalk or resin, as that is too fierce, indeed the pegs may 'freeze' in and you may end up with a split pegbox.
The peg compound is available for a very few quid.