I have two old coins that are dipped in resin/sap stuff.  Lately it
seems the resin has become sticky and it's slowly falling apart.  How
can I preserve it so it doesn't get damanged?

HI,
I don't understand something.  Seems to me that the coins are what is
important, and not the resin or lacquer, whose purpose I can't fathom.
 If it was someone's idea of a way to keep the coins (silver, copper?)
from tarnishing, then it isn't important  - shouldn't be there from a
coin collector's point of view (which I ma not).
Maybe you can explain a bit more, preferably as a comment so that we
can see that the count has increased.

The coins in resin are on a chain (it's like a necklace).  It was
given to me by my grandmother and it's important that the coins stay
in the resin.  The coins themselves aren't valuable but the dates on
them correspond to the birth of my grandmother's parents.

HI, 
Okay, I appreciate the significance of the coins, but still not that
of the resin.  Is that what is holding them to the chain?  Or
protecting them from tarnishing?
It seems unlikely that the resin's deteriorization can be stopped, but
cannot then another solution be found to do whatever it does?