Quoting Hans Dendauw
Nice work. A suggestion for cleaning those yellowed whites: OxyClean and water in a zip-lock bag, placed in the sun (UV light is important) for up to 24 hours. This works fantastically! I found that it also works on grey, but do NOT use it on dark colors, especially black.~H
Thanks, I will try it in summer ... or when the sun will be stronger. Thank you very much! =)