It may well help with airborne dirt such as dust and grime
If your water is hard (or perhaps if it's anything other than very soft) then maybe doing the final rinse with deionised or distilled (expensive!) water might be a good idea, to prevent calcium and other minerals or carbonates being left behind and blocking the pores of the carbon?
good thinking that missy and i just happen to have a big bottle of distilled water siting in the cupboard,so far the first one which is the used and rewashed carbon has been in place a few days now and the room is smell free even my resident sniffer is happy so i am also happy enough as long as it continues to work as well the tangerine dream is the best test as is the strongest smeller i grow!,i shall have to look into a cheaper source of new filter carbon as the stuff from greens has gone right up in price since i last bought it and its surprising how much is needed even to refill the 4 inch cfs,i think i bought 10kg last time but sure it was not near the cost now!peace