removing old vinyl from backlit panels

[2B]

it looks like an illuminated cabinet frame, is that the case?
if it is backlit, then yes strip the material off or do a new panel.

If it is NON-illuminated then reface it, take a piece of opaque white vinyl cover the section up and then lay the blue lettering.
This will be the fastest and from the sounds of your customer will also fit into their budget. I would also have them sign a "reface waiver" exonerating you from any future issues they may have



regarding the blue lettering YIKES!!! for only being 4 years old that is HORRIBLE. I would be willing to bet the person who laid the blue the first time used some bottom dollar, temporary or indoor grade vinyl

 

[player]

There is a large pylon sign near me that has that same crackly blue background for years. It is only crackling on the side that the sun hits it.

It has looked like dog sheet for probably 7 years... It's the whole background of this big sign. All the crackly bits are all dirty and pealing now.