Oxallic acid has shown great promise over the last several years in fighting Varroa. Oxallic acid is an organic compound which is found in leafy greens, vegetables, cocoa, nuts, and seeds. Simply place the oxallic acid in the cup at the end of the vaporizer. Place the heating element in the hive until it is centered in the middle of the hive body. You will also want to adjust the reducer gate to seal the the entrance reducer. This is very important that the front of the hive is completely sealed and not allowing bees to escape and the vapors to leave the hive during the treatment. Next, connect the vaporizer to a car battery. Then you will wait for approx 4 minutes for the oxallic acid to completely vaporize. Then remove the connectors from the car battery and then remove the vaporizer from the hive.
In order to properly treat for Varroa, you will need to repeat the treatment 10 days after the first treatment and potentially again on day 20 after the first treatment. This allows the Varroa which is in the capped cells to rotate out. Oxallic vapors will not treat Varroa which is in closed cells. This is why you will have to treat every 10 days to watch the mite drop after each treatment.
We would also recommend using a screen bottom board which has a sticky board. This will allow you to see your mite drop after each treatment.
SAFETY NOTE: ALWAYS WEAR PROTECTIVE EYE WEAR AND RUBBER GLOVES WHEN USING OXALLIC ACID. IT IS IMPORTANT TO NEVER BREATH IN THE VAPORS OF OXALLIC ACID.