Teak oil would probably not be a good idea as it can effect the varnish
bond. Scrub it down with an oxalic acid "wood brightener" and rinse well.
After it dries work out any remaining stain with some 120 grit sandpaper.
You might also consider flowing on a coat of epoxy to fill the checking and
seal everything before topping with a UV resistant varnish.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"wendy2b2002" wrote in message
ups.com...
I have a sailing boat that's decking is marine ply, it's showing it's
age as it was left for three years uncovered and the marine ply is,
although sound, discoloured and stained in place, as well as starting
to cracj a bit. Is it possible to apply something like Teak oil before
marine varnish to help revive the wood?