I've used blue cross country grip was on my touring skis in the past for flat approaches.  It works pretty well and is much faster than skins.  Does it mess up your skin glue?  Maybe a little but I didn't notice.  If you only apply a little under your boot you won't notice it on the down once you start sliding.  Unless the snow is very cold, then it might be sticky.  

Since I bough full mohair skins I just use those as the glide is close enough for me for most approaches.  

Thanks 2wheeler.  Sounds like a sensible solution.  For me the issue seems to arise mostly at the end of the day and there is a flat stretch back to the car and I don't want to stop and put the skins on.  I've wondered if AT ski makers could build in strips of skin like is done now with some xc skis.  Seems to me that could work well.