Felt-tip pen ink on hard hat

We have a hard hat with a felt tip pen inscription that needs to be
preserved.  The hat is white plastic and the inscription is very
vulnerable to being wiped away at the slightest touch.  Can anyone
recommend a sure-fire method for permanently stabilizing the ink, I
assume by spraying (as opposed to brushing) some type of sealant on
it.  I have not seen the object yet, and don't know if it's a
water-based ink, or solvent-based.  The curator says that even if a
sealant discolors the white plastic, that would be preferable to
losing the inscription.

My sense is that I will have only one chance to do this right, so,
any specific advice would be greatly appreciated!

Harry Campbell
Conservator
OSU Libraries
600 Ackerman Rd.
Columbus, OH 43202
614-292-9690


                                  ***
                  Conservation DistList Instance 22:64
                   Distributed: Tuesday, May 5, 2009
                       Message Id: cdl-22-64-031
                                  ***