The thing is , some curtains can be cleaned whilst hung if it is a maintenance clean, if they are really dirty( just run your fingers up and down them then rub yours fingers together you will feel the grease, if many they need to be taken down dry cleaned then re hung steamed and dressed,if you do this just use common sense, take photos, mark the swags and tails, ie number them from left to right, use a staple gun to re hang once you done a few jobs it's really simple and you can charge up as it's all time
Gary