bags so you know where each one goes when it comes time to put them back on. if you don’t want to remove the hardware, use painter’s tape to mask off each one. another way to mask off the hardware is to cover it with two coats of rubber cement. it will peel off easily when you are finished painting.
my doors were in good condition and previously painted so i only needed to lightly sand the surface to rough it up a bit so the new paint had something to grab onto. i cleaned all the doors with soap and water and let them dry. if your doors are not 