If you have purchased a sample gown or second-hand gown that is in need of some clean-up, it is generally advisable to have the gown cleaned before alterations are done to avoid trapping dirt in the new seams. If your gown has loose beading, that should be secured before cleaning so no beads are lost in the cleaning process. If a sample gown is relatively free from dirt, I don’t need to have it cleaned to work on it, but I do ask that second-hand gowns be cleaned to remove the dirt and oils that built up over the first wedding day.