John-

Shellac is used as a coating in some candies and pharmaceuticals so it
should be okay for a youngster to chew on.  I had heard it was used on
M&Ms, but that turns out not to be true.  I'd be inclined to use potable
alcohol for the solvent rather than denatured, but that may be needless
worry as I suspect the toxics in denatured alcohol evaporate with the rest
of the alcohol, but for this special job why take a chance.

Some info here:  htt
p://en.wikipedia.org/wiki/Pharmaceutical_glaze

Phil