These markers have been sitting tip down in a coffee cup since I bought them. The caps have never been taken off. I tried to use them today, and the black from both packages didn't work in the slightest.
I googled how to fix dried up expo markers, and was led to believe taping a string to one end of the marker and giving a few gentle swings around your head would fix them.
It certainly caused a copious amount of ink to come out in the cap of the marker making for a messy cleanup, however the markers continue to be non functional, tested on 3 separate white boards in case it was a surface finish problem.
I would not recommend these as a purchase, I have no idea if being warehoused in a hot environment, the shipping process, or something I can't even fathom, destroyed these markers before they were even used, but they were a complete waste of money.