Not much you can do about the fluffy stuff that will form around the terminals. That is a sign of electrolyte leaching out of the battery (cracks or bad seal between the terminal lug and the top of the battery) or discharged from the vents at the top of the battery. Even maintenance-free batteries will do this, regardless of chemistry used. Small amount of deposits are pretty normal - just wash them off, treat the terminal and lugs, and keep and eye on it. Excessive deposits could indicate a problem with the charging system - from poor or loose connections (pretty common) to the alternator overcharging the battery (also pretty common, causes the battery to out gas) to a bad cell in the battery.
Grease, dielectric, vaseline or spray - all works in these cases. Dealerships generally favors the sprays, as they can quickly hit the terminals without removing them. Works well, as long as there are not a lot of heavy deposits on the battery already, as it can't penetrate down to the terminals to effectively clean them.
If the deposits are heavy, might have to remove battery and clean it with a baking soda / water mix - careful not to short across the battery terminals as you do so. Once clean, dry the battery completely and address the terminals. If they have deposits on it - hit them with the same baking soda / water mix - might need a small wire brush or old toothbrush - clean it well. If you leave any of the deposits on it, it will just come right back. Again, dry them completely and then give the battery posts and the terminals a good coating of grease, petroleum jelly, dielectric, spray, etc. - reassembly, make sure the connections are tight and you should be OK. Just keep checking on them, as eventually, the deposits will come back.
Since modern cars have much larger electrical demands on the system and tend to use more standby electricity - seeing deposits form at some point is almost unavoidable. Best thing you can do at this point is to address it and monitor the deposits. Eventually, it will come to the point where the battery will have to be replaced.