>When you say you have to be gentle do you mean so that you dont break the cell open or do you mean that you might kill the queen inside?
I mean you have to keep them upright and not jar them at all. If you do jar them you can injure their wing buds and you get queens with deformed wings. If you don't keep them upright, the larvae can get moved or damaged in the cell. Also, a newly capped queen cell is very soft and can be squished, deformed or torn easily.