>I have heard of chemical residue building up in your wax and the cells getting smaller over time. Beeswax is a sink for all kinds of environmental contamination besides contamination from treatments for beekeeping problems. Research ( Elbert Jaycox)has shown that brood nest cells do get smaller (up to 17%) after years of use but found no problem with smaller cells. > How often should the brood wax be changed out and what problems if any could this cause in the hive? Every beekeeper you ask will give a different opinion. In days gone past comb rotation was considered a waste of time and money. Now annual removel of some comb (2 frames per hive is the most often talked about number) is considered normal. Many beekeepers which have used Apistan (fluvalinate)or Checkmite (choumaphos) or both are in the process of changing all comb (I finnished mine this year after three years of work). So far your questions have been easy. The next is complicated. "what problems if any could this cause in the hive" Tests to determine exactly which environment chemicals and levels are in your brood comb are very expensive. Tests for chemicals used to treat varroa etc.are not needed as most likely the contamination was done by you. Our bee labs have given us accurate amounts of contamination levels for per label use of approved chemicals. Illegal use falls in the unknown catagory. In my opinion contaminated brood nest comb is a major cause of hive loss in the U.S. today and base the fact on the big improvement in all areas of the hive by those which have rotated contaminated comb from their hives. Many problems such as queen raising problems (coumaphos) and sterile drones (fluvalinate) have been documented. Many other problems are suspected but hard to prove. >Also how often, if needed should the wax in the supers be changed out? I only change out super wax on rare occasions. I am of the opinion old dark super comb ddoes tend to darken honey. Rather than replace the comb I like to sell the supers with loose corners and dark comb to other beekeepers ( many calls for supers from beekeepers this year)and replace with new supers, with new frames and new foundation. Others may not agree with me but I do believe that the lightest honey comes from comb which has never had brood in it and is not very old but only my opinion. I really don't worry much about super comb. The archives are filled with opinions on brood nest wax contamination. Sincerely, Bob Harrison :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and other info --- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::