Anyone using a Fingerprint Reader?

I have a URU 4000B (Actually i have 4 of them) and they are all a little over 4 years old. All of them are pretty foggy, and 2 of them pretty much dont even register when they are being touched anymore.

We’ve always cleaned them via the manufacturers recommendation but it’s not working anymore.

Does anyone know how to replenish the pad so it see the prints again?