Is it ok to polish old 'junk silver' coins or does doing that somehow take away some of its value?

[Johnny B Goode]

Cleaning to me is no big deal cause I am thinking that them being 90% silver the value comes from the 'silver content' as opposed to having 'historical' value from the natural old circulated look. So do I clean or not clean? I tend to like thing looking shiny and new. Thanks.