Less potent desiccants are easy to find.
You can bake rice or macaroni at low heat until just before it turns brown. That gets them extra-dry.
But now you have to seal them tightly, quickly, before they adsorb humidity and lose their value. But you can't put them into plastic hot or it will melt. So pour them into some glass jar with a tight lid. As it cools, you will pull a vacuum, so crack the lid a few times as it cools to keep from building so much vaccum that you can't get it open.
Then put some extra-dry rice or macaroni into the bottom of each pill bottle to suck up any humidity that the seeds release, and what diffuses in past the (not-very-tight) seal each pill bottle has with its lid.
To keep the seeds separate from the rice, i hope you can figure out something practical! Folding one or both up in a small paper envelope seems like a necessity.
Or put all your pill bottles into one big tub or really-tightly-sealing shoebox or sweater box. Then pack the rice or macaroni into a big paper envelope and staple that closed. the humidity will diffuse rapidly through paper.
A really big freezer bag with a double Zip-lock lip might keep humidity out. Humidity and oxygen can diffuse slowly right through standard, thin Ziploc baggies and their zipper.
But lots of people just store seeds for 3-5 years in paper and never worry about humidity!
