1.1 INTRODUCTION

A PRELIMINARY TREATMENT for cleaning paper is often the use of a dry cleaning device, such as an eraser or crumbs, to remove surface dirt. Dry cleaning devices might be used when the paper or media cannot withstand aqueous treatment, or prior to aqueous or solvent treatments which could set unremoved particulate dirt. What has remained unknown to the conservator about these dry cleaning products is what they consist of and whether they have any deleterious effects on paper.

The question of whether eraser residues remaining in paper might prove harmful was addressed in 1966, when the Library Technology Program of the American Library Association commissioned the McCrone Associates to study seventeen book cleaning materials.1 The materials tested for use on paper were all deemed safe. It was postulated that the residue from some dry cleaning products would even be beneficial if left on the paper.2 This study suffers from a lack of description of how the erasers were used, and it therefore remained difficult to evaluate the results. Paul Banks, in a 1969 article on paper cleaning, urged the removal of dry cleaning residue from papers because of the possible long term destructive effect of eraser crumbs.3

Surface abrasion to papers subjected to dry cleaning has been studied by Kerry McInnis.4 McInnis was interested in whether sizing protected aged and unaged papers from the abrasive action of various dry cleaning products. In addition to the conclusion that sizing did serve this protective function, the erasers were ranked for relative abrasion of the paper surface and for the amount of residual crumbs deposited among the fibers.5

The current study is designed to evaluate four dry cleaning products and their effects on both the surface and mechanical properties of paper. The products tested appear in Table I, along with manufacturers' indications of composition. In Part I, the composition and aging properties of the erasers alone are described. In Part II, eraser treatments are performed on preaged and unaged paper samples followed by different postaging times. Strength properties and optical properties were examined and compared to untreated control samples.

Table I Dry Cleaning Materials Examined