Hi Novice,
Yes, you just let the bean pods mature right on the plant. They will change color and become hard and leathery. By then the beans inside will be hard and shiny. If you are uncertain if they have dried long enough on the plant, just pick one and look. After a little while, you will just know when to pick.
Once you pick your beans, bring them inside and shell them. Store them in a paper envelope in a dark cool dry spot in your home.
If you have bean weevils where you live though you must freeze them for a a week to kill any weevils that will be in some of the beans. Before you freeze the beans, make sure they are super dry. Also, if you wish to freeze your beans for long term storage, you must also test them for dryness before freezing them.
It is simple to do. Take a couple beans and smash them with a hammer on a hard surface like your driveway. If they smush, they need to dry longer. If they shatter, they are dry enough for freezing.
If you are just killing weevils, placing them in a paper bag in the freezer works fine. If you are freezing for long term storage, put in an airtight container. When you remove the container from the freezer to get seeds to plant, let the container come COMPLETELY to room temperature. If you do not, you will kill the beans.
Remy

Thanks so much remy!! That is really helpful. How do you know if you have bean weevils?
Also, they can just dry in my house in a paper envelope or bag?
Wow! I thought it would be more complicated than that. Thanks so much for your help remy.

Hi Novice,
You're welcome. It really is so easy! Beans in fact were the first seeds I ever saved.
Yes, you can leave the beans to dry in a bag, but shell them first. The pods could hold in some residual moisture.
Good question on how you know if weevils are present in your area. Calling your cooperative extension and asking, or talking to other gardeners if you have some near you is your best bet.
Remy

Sorry to dig up old thread, but we're expecting a freeze. I was leaving beans to dry on the vines since all the ones I picked earlier and put in web flat in garage molded. But the majority of these pods aren't leathery yet. Is there a good way to dry them to save for seed? Before or after shelling? Or do we need to eat these as shellies?

Oh, and is it safe to eat the pods, the beans, or save for seed if they have rust? I can always get more pole Blue Lake but I want to save some Cherokee Wax. Unfortunately most of the wax beans aren't very mature yet.

I would leave them on the plant until you expect it to freeze. Last year I picked some pods (Fortex pole bean) that were not full mature and let them dry in the garage. They seemed to mature in the pods. I plan to plant them this next spring.

I am guessing that the quicker they dry the less chance of mold. But I would not heat them up. If the furnace is coming on, air in the house is likely dryer that outside.