When you say "really dried-out", what do you mean?
Originally posted by Keith Mount:
What do you put on really dried-out wood to help restore it, besides linseed oil?
Do you mean wood that's sitting at Equilibrium Moisture Content (10.6-12.6 percent for Newark NJ) or do you mean wood that's been cooked in the sun until it looks heavily weather, grey, weatherbeaten and lifeless -- kind of like driftwood?
If it's the former, you do nothing. If it's the latter, you replace the wood.
Once wood gets to that state, there's not much you can do as the wood is gone, finito, deceased.
The lignin (the polymer that holds the wood fibers together and gives wood its water repellency) has been destroyed by ultraviolet (UV) light. Among other byproducts, the photochemical degradation of lignin produces free radicals and acids. Guess what happens when you dump acid on wood?
FWIW, there was a piece on Morning Edition (NPR) concerning Fort Apache on the White River Apache Reservation. It's up at 5000+ feet altitude. The US Government is supposed to be holding it "in trust" for the White River Apaches. Some of the buildings haven't had any maintenance since 1922. They quoted someone from the Apache Nation that in stabilizing one of the officer's houses, it took 288 gallons of paint to get the house painted.
You would not enjoy Nietzsche, sir. He is fundamentally unsound. — P.G. Wodehouse (Carry On, Jeeves)