My questions are worse!
I suppose you could sell them to someone that shoots color film, and then buy 120 size. Also, I don't know if this is possible, but could a repair shop convert the 220's to 120? The cost of having it done might be offset by the increase of value of the backs. The only things that might need to be changed would be the rollers and the pressure plate. Maybe this could be done by the owner if the parts were available. I have never heard of this being done, or if it is even something that can be done. Is it? Ric.