I think <img border="0" title="" alt="[Eek!]" src="eek.gif" /> they would "probably" be safe if rubbed lightly with soap and water, not letting them soak Lonnie?
I have taken Simple Green and using hot/warm water and a toothbrush used it on assorted grips and it got them fairly oil free?
Although I haven't heard of the "pressed" grips either, although I have seen the pressed paper holsters and water would be tough on them if soaked <img border="0" title="" alt="[Eek!]" src="eek.gif" />
Ed