The gel works ok to mask odors, but tends to leave this "chemically clean" smell , especially in smaller areas... Kinda like industrial bathroom air fresheners in malls and hotels and such. If you can put it right next to the exhaust outside the cabinet/box then you should get good results.

"Why does it smell so hospital clean in here?" - Heh that would get me busted faster than the bud smell

Theres some good plans for a scrubber type filter on here somewhere - thats your best bet if you have the space and a little time/money

Good Luck!