Tess,

I have a block of Beeswax which has been in my family since the '50's. My father used it to wax the bowstring on his heirloom English Longbow. The outside does get a bit whiter after a few years but I simply dunk the entire block in a double boiler.

Now perhaps it is because the block is large that a little drying out of the outer layer is small in relation to the total volume, but this block (about 2 1/2 pounds left after all these years) has been melted and re-melted many times with good success.