I'm not sure you intended to be in the Tool Forum. I doubt there is a good tool for this other than a vacuum; and I doubt it would work either; but might be worth a try.

You might hope that most of the bugs really like your non herbs and go for something nasty. I bring elephant ears and impatiens in for the winter. They sometimes bring in or attract white flies. I nuke um with Seven and they are gone! If you sprayed the regular plants, perhaps the bugs on the herbs would migrate over to them and nuke themselves. Might be worth a shot.

Your problem and the answer is related to a combination of soil choice/composition and watering habits, possibly to fertilizer choice as well, if you're using an organic nutrient supplementation regimen.

For lots of input, ask your question over on the container gardening forum.

This thread, about soils for container growing will help you avoid most of the issues many container gardeners are forced to address as a result of soil choice.

Al

They called fungus gnats they after vinegar as food source they feed on as start to vinegar, that happen in potting soil in house that where lay eggs. Cider vinegar trap best to catch adults gnats take fruit jar put little in bottom a amount drown gnats in top lid punch small holes just larger than gnats they enter jar can't get out fall into liquid die they die in light fixtures as well. The adults need die before lay eggs a vacuum cleaner help collect adults it taake month brake cycle. Any over ripe vegetables fruit feed adults. I put 6 jars with Apple vinegar catch gnats 2 inches deep in bottom jar ice pick hole all way in lid make about right size hole 12 holes in lid works me. .