Erasers are fairly expensive, but there are plenty of instructions on the internet of how to make one yourself cheaply
(HERE is one example).

Remember though over exposure will damage EPROM's!!! If you are to build one, it may be an idea to incorporate a timer onto the box
which will automatically turn off the UVC tube when enough time has
passed.  Also, VERY importantly - NEVER look directly at a UVC tube when
lit as you will damage your eyesight permanently!  These tubes are
dangerous which is why purchased erasers have all manner of safety features,
such as auto-off when the drawer is opened.  A homemade one can be just as
safe though, as long as proper care is taken.