Most charge by the pleat. However, having cleaned drapes for another franchise, I would gladly let a dry cleaner do the job. Many if not most are dry-clean only. Any water at all would ruin them.(drapes are very expensive to buy and pay someone to place the drapes back in place, because she doesn’t trust you any more). Hands held in the air holding the extraction device and hose. It is allot more work than upholstery and requires more skill and care too.