Is there a limit to how old unused WX Block should be kept? I use a bit over half doing a full polish/seal/coat on my Pegasus. Since I only do the shiny-up work every couple of years due to general laziness, I'd like to use the leftover stuff to avoid wasting it (and save some money.) I keep it where it won't freeze as that is specifically warned against on the label. And is it a good/bad idea to use something like Mother's Gold Carnauba wax over the WX Block?