The Varroa Mite Counter Jar is an effective way to check mite levels.
Fill the bottom jar with 50-100ml of rubbing alcohol or windshield washer fluid, add 1 cup of dead bees and shake for 90 seconds.
The alcohol allows the mites to fall off the bees and collect in the opposing jar. If your sample contains mites, they can now be easily counted in the bottom of the jar.
This jar can also be used with the sugar roll technique.