This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
After having considerable trouble in keeping my paper prints in the hypo fixing bath from curling, which would force the edges out of the liquid, I found the plan here illustrated a success. I procured a piece of wood, the size of a postcard, and stuck four glass push pins into one surface, one at each corner, and fastened a handle to the center of the upper side. The papers are first placed in the bath, then the board is set over them with the pins down. This holds the prints under the liquid but does not press them tightly together. - Contributed by J. J. Kolar, Maywood, Ill.
Ill: Push Pins on the Under Side of the Board Raise It and Provide a Space for the Prints in the Liquid
A piece of an old gunny sack Will polish brass work very nicely.