Dirtex is very good. It's what we use out in the field. If you're still having streaks or spots you can't get off there's a variety of things to try including pumice powder or 0000 steel wool to get any hard water stains off. Make sure it is Quadruple zero steel wool though so it doesn't scratch. Always test in a small area first. If you try these latter options ask us first. Sometimes we've seen issues with the silvering on the back when installers use the wrong glue, or when mirrors get really old and the steam strips off the backing. Damaged drywall that hasn't been painted over can sometimes have a reaction with the mirror backing too.
Metoo
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