Dont use GT-85 nasty stuff,
For oil bath and air forks the best stuff to use is a fork oil like 20wt oil, eg. Rock Shox's red rum or Silkoline and make the external seals wet with it and cycle the forks a few times, this coupled with regular servicing (every 9 months of frequent use) should make them run sweet, make sure whatever oil you use dosn't sweal the seals (alot of expensive motorbike fork oils do!).
For "dry" forks that have elastomers and springs and use grease inside rather than system oil just use a Teflon fortified grease eg Judy Buter as it was or Silkoline RG2, DONT use products that contain LITHIUM.