There are 2 ways I remove grain from footage. The easy way is to take the footage to a production house with a "drop out compensator/ noise reduction" unit. have them run the footage through that onto another tape. Saves tons of time. The secound way is to double up the clips, one on top of the other, them apply a gaussin blur to the above clip, then bring down the opacity of the above clip to suit your tastes. Either way you end up with "soft" looking footage that isn't quite as grainy.
good luck!
Kevin