Wax moths are part of the ecosystem of the beehive. In the wild they do their work to get rid of old comb that might have disease lurking in the cocoons and to free up space in an abandoned hive to allow a fresh set of bees to move in and build new comb and establish a new colony.
However, for a bee keeper the wax moth is not so desirable as they can easy take out an establishing hive with two weeks. As most bee keepers only check their hives every two weeks or so, this is ample time for the wax moth to greet you with an abandoned or dying hive and a sad moment.
There are two breeds of wax moth. Galleria mellonella (greater wax moth) and Achroia grisella (lesser wax moth). Both will invade unguarded comb during the season when they are active. Note the unguarded part, this is the secret to evading a wax moth infestation and a dead hive.
Prevention is not to give bees more territory than they can guard. Don’t leave a lot of drawn comb on a hive that is small and struggling. This was my mistake. If you end up with an infestation, the solution is to reduce the territory (i.e. the wax surface) to just the space the cluster of bees can cover and ensure that the hive opening is easy defended by the bees (ie small). Remove all the rest of the comb.
If you have a freezer, freeze infected frames it to kill the moths and eggs (this only takes four hours only). You can also just let the moths finish cleaning it up. If they get to go to the logical end they will turn all the comb into webs that just fall out of the frames. Freezing is a way to save the comb if you need it.
If your beekeeping government regulations allow, foundationless frames are great as you can put them in a hive and it’s just empty space for future expansion and not surface area to guard from the moths. I made a mistake in giving my hive some extra foundation frames, which the bees could not use and it only fed the wax moths (allowing them to populate to the extent that it then killed the hive).
Once the frames are frozen and free from wax moth, you can put them back into a strong hive and the bees will clean up the comb and use the wax and any resources left on the comb.
Apparently some people use Bt (Bacillus thuringiensis) spray which is sold as either Certan or Xentari, on the combs (I have not tried this myself). It reportedly kills the moth larvae and has no ill effects on the bees. and can be sprayed on infested combs even with the bees on them to clear up the infestation. It can be sprayed on foundation before putting it in the hive and on combs before storing them.
Another way to reduce the risk of ending up with wax moth is to trap them before they get into your hives and the bees have to deal with them. A trap for the moths consists of a two liter soft-drink PET bottle with small holes in the sides and a mixture of vinegar, banana peel and sugar syrup. The moths fly in the holes in the sides, drink, try to fly up and get trapped and die. Full details here.
The video below shows the easiest way to clean up infested frames if you are happy to clear out the wax and then reuse it later.
You can also use a heat gun to clean frames up prior to them going back into the hive if you suspect they may be infected.