Yup, very literally, just rub the eraser across the edgecard connector's contacts to make 'em shiny-n-new lookin' before re-installation.

Keep the heel of one hand touching the sheet metal of your case while it holds the SIMMs in place and buff 'em up with a soft, CLEAN eraser on a pencil or the hand held type. Color doesn't really matter, but use the kind for #2 pencil, NOT the abrasive ones for ink.