The solar lights I have bought usually in a year or two go bad because the plastic cover over the solar cells becomes cloudy thus blocking out light to the cells. So, the solar lights themselves become useless. Is there a way to restore the plastic covering? After taking one light apart I found that the plastic covering and cells were joined together and replacing the plastic was not an option. Is there a way to restore or is it now garbage?
It’s probably not the cloudy plastic, but bad batteries.
See if the batteries are replaceable.
To make the cover clear again you could polish the plastic cover. Use some automotive rubbing compound followed by a fine polish. I use silver polish but car polish should work as well.