I placed harvested sacs in a pollen box with a few silica gel packets. Figured the dessicant would dry it out plenty. Do you think it’s moldy? These were also harvested from a reversed plant, so I was thinking there could be some kief mixed in there by accident.
Sounds like it might not have been ready to harvest the pollen. Drying out immature pods will not yield viable pollen and the method you used likely contributed to moisture. You should make sure the pods are ready by opening one up if they don't open on their own. Then dry them in open air preferably in low humidity conditions before extracting the pollen. But they should open on their own and all you need to do is catch the pollen.
Typically the pods should release pollen on their own when they're mature. Sometimes with reversed plants they don't always open like they do with a true male but the pollen should be yellow and can can be collected by manually extracting it from the pods. It's tedious but I've done it in the past with reversed plants that wouldn't dump the pollen without some help.
Here's a plant I reversed last spring. I wait until the pods start to open up on their own before collecting the pollen.
Collecting is as simple as putting the parts with the pods over a plate, bowl, aluminum foil, black paper, etc... and collecting it as it falls.
Excess pollen can be sealed in airtight containers, vacuum packed, and stored in the freezer for future use.