1) Remove the lens from the gauge cluster. Clean everything with damp paper towels. No use putting a dirty dash cluster back in.
2) Thoroughly clean the lens with dishwashing soap, allow to dry.
3) Work in a well lit area.
4) You'll need a dremel drill and several muslin buffing wheels for a Dremel. I get them at Harbor Freight.
5) I used "Meguiar's Ultra Finishing Polish 205" https://www.oreillyauto.com/detail/megu ... brand=true
6) smear about a dime size blob onto the lens and wipe it onto a small area with your finger. Set your dremel to as slow as you can, then start polishing with the spinning muslin buffing wheel. Don't press down too hard. Just enough so you can feel the buffing pad working on the plastic lens. Don't be in a huge hurry. Do both sides of the lens, wipe off, wash and check to see if it's clear enough. If not, buff some more. Keep applying the 205 to new areas as you work. You can check how the clearing up is going by sighting through it into the distance. At first, items in the distance will be quite dim. When you're done, it will be clear, albeit a bit wavy, which is how they were from the factory. Because, you know, plastic.
7) Clean all the 205 residue off and gently wash with dish soap and dry with soft clean rag
8 ) Use the same method as used with the 205, but this time with "Meguiar's Synthetic Sealant 2.0 #21" https://www.oreillyauto.com/detail/megu ... brand=true. This seals and prevents re-fogging for quite a while.
9 Clean, dry, admire the clear lens! Some discoloration from sun may remain. Not much can be done about that, but the lens will no longer be foggy!
10) Clean, mask and paint the bezel. I used Rustoleum Metalic "Dark Steel". It sticks to plastic just fine without priming. I touched up the F-O-R-D letters with black model paint and a fine brush.
11) Reassemble the now-nifty dash cluster and reinstall the dash cluster in the dash of your truck.
12) Celebrate with an adult beverage or iced tea

This is a foggy '69 dash lens: This is a cleared '72 lens using the described technique: After painting the bezel and reassembly: