Ballscrew wipers?

I am working on the antibacklash
mechanism for two standard
5/8 ballscrew nuts the next step is
to come up with some sort of wipers
to prevent contaminates to get into
the nut housing durring operation.
I am thinking of designing something
made of nylon to mount on each end of
the unit.
Any Ideas materials and ways to mount them?
I try'd to find some examples on the web
but was not able to find any good examples.
Somebody must have done this before right.