There are three common methods of covering jelly tumblers: (1) Dip a
piece of paper in alcohol; place it on top of the tumbler as soon as the
jelly is cold; put on the tin cover and force it down firmly. (2) Cut a
piece of paper large enough to allow it to overlap the top of the
tumbler at least one-half inch on all sides; dip the paper in
slightly-beaten white of egg; cover the glass as soon as the jelly cools
and press down the paper until it adheres firmly. (3) When the jelly has
become cold, cover the top with melted paraffin to a thickness of
one-third of an inch.
To mark jelly glasses sealed with paraffin, have the labels ready on
narrow slips of paper not quite as long as the diameter of the top of a
glass, and when the paraffin is partially set, but still soft, lay each
label on and press gently.