I've been wondering about this too.  A film of mineral oil floating on a cup of tea with my honey in it would be unacceptable!  I know someone who was using Crisco patties year-round for a while.  She had no sign of mites but there was an oil slick on her tea.  I'm not that desperate yet.  Hopefully this isn't a problem with the current system, but I'd like to hear more on the subject before I oil up my equipment.
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From:   Trevor Weatherhead[SMTP:[log in to unmask]]
Sent:   Saturday, July 05, 1997 7:20 PM
To:     [log in to unmask]
Subject:        Treatment for varroa using mineral oil
 
there is one aspect that has not been raised to date which I believe is
important.
 
Does the mineral oil become a residue in the honey?  Judging by the
application method there must be a possibility that it will enter the honey at
some time.
 
I realise that it is food grade mineral oil that is used but, as mineral oil
is not a natural occuring part of honey, then any that finds it way into honey
must be classed as a residue.  We now have greater standards for honey being
required throughout the world.