In the case at issue, the original check amount in words and numerals had been erased and corrected to significantly larger sums. No signs of mechanical erasure were visible under microscopic examinations; however, small ink deposits were visible. Optical examinations with infrared reflection and luminescence showed that, in some cases, the inks used in writing the check amount were different from the original inks used in the signatures. In testing related to issues involved in this case, 13 sheets of photocopy paper were marked with each of the 14 ink pens, and then each of 10 test products was applied to each ink type, such that each sheet was tested with a different test product. After the liquids had evaporated, their effect on each ink was noted. A second series of tests was conducted wherein the 14 pens were used to write out checks belonging to three banks. Each check was then treated with one of the three test products ("Ricomatic," "Stain Devils," or "didi seven." As a third stage of the experiment, each of the test products was applied to segmented portions of all four banks' checks. Generally, the test products did not affect the checks to an extent that would necessarily arouse the suspicions of the check's receiver. To prevent potential forgers from attempting such erasures for fraudulent purposes, banks should consider using some form of security paper or printing in their checks that will exhibit a significant change upon applying the tested products. 2 figures, 1 table, and 3 references