With regard to the 4 off 52mm Smiths gauges (oil, fuel, temp and amps), what is/was the original material on the underside of the bezel? I am referring to that which is between the bezel and the glass.
On my gauges the material has seemingly decomposed and "bled" onto the outer face of the glass.
A Utube video I found shows some kind of butyl being used - but this looks messy and awkward.
Can an O ring be used? What have other people done as I would imagine the issue is quite common.
Note: "Yes" O rings are available from Smiths specialist suppliers, but these are the flat O rings which sit between the gauge and the dash upon installation.