can these be refreshed by washing?

Dear Cynthia, thank you very much for your message. Yes, you can wash your insoles with some soapsuds or some shampoo. After washing them, please let them dry at room temperature and please, do not place them on the heating. Moreover, it is important that you put your insoles on the woody side. If you have any further questions, please don't hesitate to contact us again. Best regards Pia Schmidt ZEDERNA

Is formaldehyde used in manufacturing these?

Hello, we can assure you that no formaldehyde is being used in the manufacturing process of our Zederna Cedar Wood insoles. Kind regards from Zederna

Anyone have an effective solution to keep them from moving? These work great, but they keep migrating up behind my heels

I think you may be getting the wrong size. I've never have that problem myself. If it's not a size issue, what about a doble-side adhesive on the bottom?

Do they prevent static electricity

Hello, unfortunately our insoles do not prevent static electricity as they are made from solely natural marterials ( one layer of cotton and one layer of cedar wood).