Everyone has their own ideas. Many, such as myself, draw a line at anything more than the most subtle cleaning. I use water, Qtip and a Hi Polymer eraser. It is an art eraser that crumbles easily and is much better than ordinary erasers to help prevent damage to paper when it's rubbed. Under $2 delivered
https://www.ebay.com/sch/i.html?_fro...eraser&_sop=15
.