After drone laying workers have got into the flow hive they leave greasy larvae casings and black spots which cannot be cleaned by running under the tap and can only be cleaned by dismantling the flow frames and scrubbing each strip in hot 70C dish detergent. This is a lot of scrubbing. Should I use soda on the flow frames? Can I put the flow frames in a dishwasher? Should I use pressure washer the kind you use on the car?
I sprayed mine with a garden hose and they came clean, but I got to them quickly, and most were juicy larvae and uncapped. (I had to pull the little buggers out with a tweezers and the birds were very appreciative for the treats.)
I used garden hose as well. Some capped. Water cleaned them out well but did leave dark residue around the edges of the bottom of the cell. Figure it is no different than them reusing drone cells for honey.