I have been given some flow frames that have had brood in them. They are black with propolis and brood wax. I have pressure washed them and removed the old wax but the black refuses to budge. I have pulled one frame apart and soaked it in Betsy and then Napisan. A lot of grot came off but I still had to scrub each component individually to get it clean. Are these frames destined to be brood frames forever, or will the bees clean them up if I put them in the super?
Flow usually suggests just opening the cells to the harvest position and hose them out. Allow them to dry in the shade. The bees will probably clean up the rest once installed back in a hive.
One thing I found worked for a client’s flow frames that had a lot of propolis & brood wax & casings is to leave them in a shed for a few months to let the wax moths clean them up, which they do beautifully, after which they just need to be hosed out.