[Mgs] Rectangular Bezel Removal

[Bert P]

Hi folks,

I have an electric clock, about 30 x 40 mm, in one of my other British cars.
(That is about the size of an oil pressure gauge on a late USA MGB).

It worked previously, but did not resume service after I had the car 
stand unused for a little over 20 years.
So, I would like to open the clock, but I am very reluctant to pry 
the bezel off.
AFAIK that is the only way to reach the interior.
I'm afraid the ridges of the bezel may break off.

Any suggestions on how to proceed?

Bert,
Holland, Europe.