Not sure how many of you beekeepers out there are readers of American Bee Journal but there is a VERY interesting article in the January edition written by Randy Oliver on page 43 that goes over a new varroa mite treatment he has been doing research on using food grade vegetable glycerin/oxalic acid solution that is soaked into paper shop towels and layed on the top bars of the frames. It appears to be VERY effective and an excellent treatment rotation to whatever you may be using now. It would also be a LOT less hassle to apply this treatment than sublimating oxalic acid into the hive. Very economical to use as well.