The Abbey Newsletter

Volume 25, Number 5
Feb 2002

Eraser Crumbs of Staedtler Mars Plastic and Eberhard-Faber 1954 "Magic Rub"

By Bill Minter

Many conservators have discussed the merits of ground erasers for cleaning paper. The microscopic examination of paper cleaned with Skum-X and other dry cleaning powders reveals tiny particles that cannot be removed with a brush. The residue, along with other substances in the powders, is a great concern. It should be noted that manufacturers will substitute ingredients and that one of the powders is made from natural rubber. By grinding block erasers of a known quality, we are assured of the best treatment. By controlling the size of the crumbs, we reduce the chance of any residue in the paper.

For years, many conservators have relied upon grinding their own erasers. The traditional kitchen grater as well as hand-held cheese graters and food processors have been used. These devices do an adequate job initially, but eventually the parts wear to the point that metal particles begin to appear in the eraser crumbs. Another problem is that these machines break down quickly because they are not designed for the purpose.

At the 1994 American Institute for Conservation Annual Meeting, the Book and Paper Group had a Tips session. As usual, there were a number of ideas that are beneficial to the conservation of paper and books. One tip of interest was the use of the Italian Fimar Cheese Grater for grinding the erasers. The idea, which originated at the Frederick Law Olmsted National Historic Site, National Park Service, was presented by Elizabeth Morse, currently of Harvard University. Elizabeth, Mimi Batchelder, Wendy Gogel, Elizabeth Banks and others had spent many hours examining and discussing the benefits of grated erasers and ways to obtain them. They eventually found the Fimar Cheese Grater. It is a high quality, industrial machine that is made of stainless steel which has been modified for grinding erasers.


A brochure can be sent that has samples of Staedtler Mars Plastic and Eberhard-Faber #1954 "Magic Rub" eraser crumbs. Both are available in crumbs of four sizes of grind—Fine (F), Medium (M), Coarse (C), and Extra Coarse (X).

Block erasers without the ink-imprint are ground in the Fimar Cheese Grater which has a stainless steel grinding head. Further grinding is accomplished in a modified commercial blender which is also constructed of stainless steel and Lexan. The resulting crumbs are sifted through various sizes of stainless steel mesh as listed below. The crumbs are packed in cellophane bags which are heat sealed; two four ounce bags are packed in a "Zip-Lock" polyethylene bag. Each bag is dated. Every attempt is made to keep the eraser crumbs as fresh and as pure as possible without contamination from any other substance.

In addition to the cellophane bags that are used, we are also suggesting further protection in either a glass or plastic container to reduce the possibility of loss of plasticizer. This should ensure a fresh product even after long term storage.

Fine smaller than .021" Very Smooth Paper
Medium .021" thru .045" General Purpose
Coarse .045" thru .097" Rough Paper
Extra-Coarse larger than .097" Cloth Backed Items


#1954 Magic Rub $13.00/pkg.
Staedtler Mars Plastic $16.00/pkg.

Shipping and Handling:

To make it easier for everyone to calculate the shipping and handling cost, we will use the following:

1 - 3 packages $20.00
4 - 6 packages $13.00
7 - 10 packages $16.00
10 - 20 packages $19.00

Reminder: Eraser Crumbs are also available from BOOKMAKERS INTERNATIONAL, Riverdale MD, ph: 301/927-7787.

Special Offer: A shaker/container will be supplied at no additional charge with first time orders of six packages or more.

Suggested Reading

Elizabeth Moffatt and Marilyn Laver, "Erasers and Related Dry Cleaning Materials." Canadian Conservation Institute, CCI Analytical Report ARS No. 1738. 1981.

Elizabeth Moffatt, M.C Corbeil, S. Guild, and C. Emond, "Analysis and Assessment of a 1994 Test Formulation of Skum-X." Canadian Conservation Institute, CCI Analytical Report ARS No. 3288. 1994.

E.J. Pearlstein, D. Cabelli, A. King, and N. Indicator, "Effects of Eraser Treatment on Paper." Journal of the American Institute for Conservation, Vol. 22, No. 1. 1982

If you have questions and/or comments, please contact William Minter Bookbinding & Conservation, Inc. at 4364 Woodbury Pike, Woodbury, PA 16695; ph: 814-793-4020; fax: 814-793-4045; email:

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