Hello Waynne,
Clouding is probably a reference to an insulated glass unit that has failed, i.e. moisture has gotten in between the pains of glass. Our insulated units are guaranteed for 20 years. Failure of insulated glass is prevented by keeping moisture away from the seals around the edge.

Spotting is of course maintained by cleaning, but now an additional treatment can be applied that causes water to sheet off more easily. It is like clear teflon. The glass industry calls it self-cleaning glass, but we prefer to describe it as easier-to-clean.

Thank you for your question. I hope this helps.