I had these two, shall we say inexpensive gift, flower vases covered in an etched glass-like paint which was beginning to wear off. I treated the vases to a few coats of paint and a polka dot motif, then cured them in the oven by putting them in a casserole dish with lid just in case they broke and put them in a cold oven. Then I turned the oven on to 350 F and set a timer for 30 mins. When the time was up I turned off the oven but left the vases inside to cool as the oven cooled. Now they should survive a trip through the dishwasher on the top rack.
The paper clips are set up to hold the vase slightly off the base so it can dry.