Moving driftwood between tanks?

Should I boil it - just resoak it - or just scrub it?

You're just moving driftwood from one established tank to another? I wouldn't do anything to it. I mean you can do the usual boiling/scrubbing thing if you want to but I don't think it's needed.

If you have BB algae built up on it I'd use the occasion to scrub it down good. Otherwise if you take it from a healthy tank w/out no sicknesses and move it to another just do it, no issue had done that a million times (yes I love redecorating my tanks). Just if its a super large piece that is failry new watch your pH/ KH it may drop a lil if the tank's volume is small in relation to the DW piece.

The piece is fairly new - but its not done anthing but turn the water brown. I bought it to lower the pH - but it hasn't touched it and its probably because my water is so hard.

Dep on your exact water parameters (pH and KH) and the numbers you want to get it to you may be able to work with peat; I used it before for the same reason (for killi's) and it worked great.