1. Dismantle everything until u take out the LCD from the panel.
2. Peel off the original polarizing film from the LCD.
3. Clean the remained glue on the LCD.
4. Prepare a fresh polarizing film and put it reversely (until you see background become dark)

For 2 and 3, these are extremely dangerous and you have to brave anuf and experience to do that. Any wrong you will have to buy a whole new meter just because of the LCD.

For 4, mostly impossible you can find a fresh polarizing film, i took it from my spoil 10 years old digital diary and cut it to fit. Anyway, no need to glue the new film, just put underneath the LCD will do.

Yes. Once you feel off, the polarizing film can't be reused anymore (like you peel off the tape), you have to get a fresh one.

So far i dun know where to buy the new polarizing film. As I said, i took from old spoilt digital diary, that polarizing film is just attached without glue so i just cut and fit in my display panel.