The only thing I do, which seems to work well, is to dry them until I can snap a seed in half, between my fingers. Then, they need to be stored in a dry place. It sounds like you didn't get them dry enough, or else, your garage is too damp.

George
Tahlequah, OK

you are probably right on both accounts....I washed the seeds just to get some of the slim off and laid them on a cookie sheet and dried them below my ceiling fan...have a wood stove in the dinning room...after which I put them out in the garage but I always felt there is to much moisture in the air because my winter squash never last as long as I think they should..have to work on some kind of storage room/...

You may want to try using something like newspaper to dry them on as it will absorb some of the moisture. After a few days, flip the seeds so they can completely dry out the rest of the way. You may get some newspaper stuck to the seeds, but that is okay. The seeds will still grow fine.

I actually had this same sort of problem with a seed exchange that I had earlier this year. I am going to try to plant the seeds anyway and see if I still get anything.

Good luck next time.

Dry them at room temperature, but don't heat them. It may take a couple weeks to get them crispy so that they snap when bent. When finished, you should be able to place them all in a jar and shake them up with no signs of anything sticking to anything. Then keep in dry, cool, dark location.

My room was heated by the wood stove and I only let them dry over night...I thought they were dry and at first put them in a plastic jar but within a few days they were growing mold and I even had some sprout...so I redried them, laid them out in a box and put them in the garage...well maybe I won't end up with many of these, so I'm making sure I restock my supply of seeds...

i had the same problem, just threw the seeds away today, all covered in mold :(