Sevin Dust is probably not the best thing to use. Greenlight is
pretty good. The 0.05% concentration of Deltamethrin has a very low
toxicity to humans.

If you can go three weeks without seeing any yellowjackets, PLUG THE
HOLE THEY USED TO GET IN! If you don't, six months from now, when
most of the Sevin has blown away, a new colony will move in, attracted
by the smell of the old ones.

I have to kill wasps, bees and yellowjackets in soffits several times
a year (professional exterminator). I usually go there when it's
convienent for the homeowner or resident, which is usually about 9am.

Needless to say, I wear a bee-suit. In treating bees I use Wasp
Freeze, Delta Dust, Diatomacious Earth, Lesco Flushing Agent and if
it's a commercial building I may use Drione.

If you ever get bees, you MUST have the honeycomb removed within two
weeks! If you don't, it'll melt, ruining your walls, carpet and
friendship with your neighbor. Then come the ants... millions of
them. Then come lots of stray bees who can smell the honey...

Always best to let a professional do it and take responsiblity for it.

Try alt.consumers.pest-control for more information.