are the covers glass or plastic?
If it's plastic, there are a number of products (all of which the names elude me at the moment) that'll help make the lense clear again. I believe most will need to be done a few times to make the cover "like new" again. It's been discussed in this very forum before. It should turn up with a search.
If there glass, are you sure the "cloudiness" isn't condensation on the inside? If it is condensation, you might be able to clean it up by disassembling the unit and cleaning the inside of the lens.