We have finally made it though the sanding and are doing a final cleaning of the floor. We bought tack cloth which seems to have something sticky on it to pick up the dust. Will this sticky stuff hurt when putting on the poly or does it just stay on the rag and not on the floor. Should we go back over the floor with something else.

Shouldn't affect anything; but you could wipe down a spare piece of hardwood and apply a test coat on it before proceeding if you have any concerns.