One thing we used to do was to just totally remove the green diffusers if you happen to be in there, so all of the light from the bare bulb gets out, the white background inside the housing acts as a diffuser/reflector by itself.
The back-lighting will be white instead of having a greenish tint but it's a lot brighter. Even if you want a green tint then you can buy modern bulbs with the green coating. They are still diffused with the coating but brighter than a clear bulb going through one of those diffuser covers, you can even change colors easily that way such as to red which is better at preserving your night vision if your deep offroad at night where there are no city lights.
I know this isn't a fantastic quality picture (iPhone 5s in total darkness) but the other day I took the oil pressure gauge out of our Laredo and put it into our Limited and while I had it out I reached in and popped the diffuser loose, then with a pair of long needle nose pliers I crushed it and withdrew the pieces through the hole so I wouldn't have to open up the gauge. Then I bought a new bulb but that had a green coating from the local auto parts store to use with it. This is what it now looks like next to the alternator gauge (I plan on doing all of my gauges) which is still using the diffuser with a white bulb...
SouthernGypsy's current Jeeps:
1983 Jeep CJ-7 Limited 4.2L ~ Daily Driver, Prepping for a 2 month Tour of America Summer 2014.
More Mopar Muscle Cars, Grand Cherokees, Cherokees, and ATV's than I care to count!