Any ideas about what I should do with these swords?

You say you practiced martial arts with them. Do you practice with a dojo, students, partners, or teachers who would give them a good home, or guide them to someone who would appreciate them properly?

Even if not, perhaps there’s a dojo in your area that would be pleased to acquire them for students who can’t afford their own, or somesuch.

Perhaps you can find a blacksmith or someone who crafts in metal who would appreciate the donation.

Give them away to a very enthusiastic free recycling group… Freecycle.org

Donate to a museum

I like @laureth‘s suggestion.

I was going to suggest Freecycle, myself. Freecycle rules.

Pass down to your friends, children, or put your sword in attic to collect dust.

I also agree with @laureth. My dojo loves to have spare weapons around so that people can start learning how to use them before having to invest in anything. They’re also great for when someone forgets or for surprising the lower ranks with an advanced lesson.

I would contact where you took the class, and ask to have them give them to a student who is short on funds.

As others have suggested, I’m sure that there is a worthy student at a local dojo that would appreciate the gift.