Buy a large rubbermaid tote...
Hang string inside of tote to hang buds
Install 1 or 2 computer fans in the side, blowing out.
Attach fans to a car battery.
Make a passive air intake (just cut a small hole near the bottom)
Stash the whole unit somewhere out of sight/out of smell.
Something like this (sorry drew it kinda quick)
If you want you can camo it up and install a cheap $30 solar panel to last however long you want. You can also do this inside, just add a carbon filter or vent it into a smaller area with an ozone generator. Hope this helps!