I have two young nieces who like to play with the putting green equipment in their back yard. I want to make sure that they're not handling anything nasty, and in particular I want to ensure that the metal bases of the flags aren't made of lead or some other harmful metal. What are golf cups made of?
Cheap ones are made of plastic. These would not normally be found at courses because they would crack, chip, and wear out (the flag is the biggest problem). Most decent courses use aluminum cups like this.