Black bits

Ok, so this isn't on Skoda, but this problem must come up........

The black rub strips/door protectors/whatever you want to call them: Looks like my car's previous owner has sprayed something on the strips, which has now started to peel off with the inevitable bad looks. So, knowing something "dip and strip" will probably knacker the plastic, I was thinking of re-doing them with something like Platidip.

1) Is this a good idea?

2) What prep-work would I need to do? (Other than masking)

3) How do you look after Plastidip once applied?

4) How well does Pastidip age? Am I doing to get the usual white marks tha just plastic suffers?

Thanks