How to stop top of face shield steaming up? Soap?

[megletsecond]

I've started wearing a face shield to the supermarket as well as a mask, but the top of the face shield steams up.

Do I need to wipe it over with soap to stop it getting steamed up?

I do tend to power walk a long distance to the supermarket so it might just be that I'm warm and it's going to steam up anyway. But NHS staff work with shields and I assume they can see out of them.

Shaving foam, wipe on and buff off again

They don't even work

Thanks great. I'll grab a can of it.