Some of mine need double brood from May - July but they always overwinter in a single box.
One colony of mine had 20 frames of brood in mid May last year.
I thought it might be hybridised but it was 85% amm according to wing morphometry.
I used it as my main queenright queen rearing colony and got a load of queens from introduced grafts.

I treat any spare comb or comb taken from dead colonies with 80% acetic acid fumes for a week.
I spent a few hours this afternoon cleaning nucs and apideas with Virkon.
I think Virkon kills amost everything apart from AFB spores.
It costs next to nothing to clean up old comb and equipment like this. Better safe than sorry.
Of course Oxalic acid is officially used as a general hive and equipment cleaner!