How do you store cleaned and washed eggshells?

You don't need to wash them or clean them, just let them dry out and grind them( not too fine) in blender then store in brown paper bag to keep dry use as needed. Personally don't think it works but it is good for soil. Just get some Nematodes

One of the fastest and easiest ways to get rid of slugs for up to six weeks is with microscopic parasitic worms called nematodes. They are watered into the soil with a special bacterium that lives in symbiosis with the nematodes and acts as food for them. The nematodes will then do the work for you by actively hunting out their slug prey. Within three to five days the slugs will swell and begin to die. Diatomaceous earth (also known as “Insect Dust”) comes in the form of a chalky dust and is the fossilized skeletal remains of microscopic creatures. It’s sharp edges lacerate soft-bodied pests, causing them to dehydrate. A powdery granular material, it can be sprinkled around garden beds or individual plants to effectively deter earwigs, slugs, and other garden pests. You can also mix it with water to make a foliar spray.

Diatomaceous earth is less effective when wet, so use during dry weather and reapply after it rains. Wear protective gear when applying, as it can irritate eyes and lungs. Be sure to buy natural or Food Grade Diatomaceous Earth, not pool grade, which has smoother edges and is far less effective. or Simply sprinkle baking soda right on them to killthem. You can also place a dusting on the soil around your plants to deter slugs from eating them – just becareful to avoid the plants themselves as puttingbaking soda on them directly will burn them. Coffee grounds scattered on top of the soil will deter slugs.Watering Schedule

Far and away the best course of action against slugs in your garden is a simple adjustment in the watering schedule. Slugs are most active at night and are most efficient in damp conditions. Avoid watering your garden in the evening if you have a slug problem. Water in the morning – the surface soil will be dry by evening. Studies show this can reduce slug damage by 80%.

I'm guessing if you let them dry thoroughly, you can just store them in the container.

There's an organic slug control I've used around hostas called Sluggo. It's non-toxic, and breaks down into harmless fertilizer.

I store mine in an old coffee can. I use more for snail control. Place in a plastic bag and whack them up with a rolling pin.

Thank you! I thought it would be alright.

Dry out and crush or blender but I also save old milk jugs and put egg shells in them, coffee grounds sometimes too, banana peels....then you have a jug of good plant water. Smells bad tho! Water houseplants before running errands!

I Put them in my flower beds year round. I do not crush them much or even at all after peeling boiled eggs. I Just crush them with my hand when using the fresh. I do not feel that grinding them up helps as it is the sharp edges that cut the slugs. It really helps build the soil by adding organic matter that is high in calcium.