I think they are only good if it’s within the day before they open naturally, but not sure about that. I know with other flowers, the pollen isn’t really viable until the flower is just about to open. Like when emasculating a flower to do selective pollination in other plants, they cut the base of the petals to open the blossom the day before it would open. Then remove male parts to keep it from self pollinating. They have to do that with peppers and berries that can self pollinate so they don’t waste their time weeding through seeds that aren’t the hybrids they’re making.
I just know that they need to be dried and sifted relatively quick so they don’t clump/spoil. The use of toasted flour or DE is to help keep it dry for storage, and to help spread the pollen more evenly since only one viable grain per calyx is needed.
In a separate closed room, I have my pollen being collected on a sheet of glass, I need a bigger piece or some parchment/foil instead.
