Visor cleaner.

[Yoda]

Okay tried and tested. Specsavers coated lense cleaner. You what? Try it for cleaning your visor. They also do two sorts of cleaning polishing cloths both a pound and machine washable. I use it on my specs and about a year ago thought "what the heck, try it on my visor." I would recommend soaking dead insects in the summer with a damp cloth to loosen them beforehand, it makes them easier to shift with the spray. The spray costs two quid a can and should last a couple of months easy.