I have an old wiper blade cut in half that I have used since the '70s, dip it in wetting agent and with the film hanging I give each side one wipe. No scratches or I would have given it up years ago.

I remember starting out, I bought a stainless steel device with two sponges at the end. It worked fine for a couple of sessions then it was scratch hell so I ditched it.
Curt