This may not qualify as a "little" detailing or "freshening", but what I did was:
-- already had an NOS tank
-- washed exterior with scour pad & Simple green. Rinse.
-- etched with POR's "Metal Ready", to phosphate-convert the galvanized steel.
-- rinsed *thoroughly*. Squirted acetone into all exterior seams to displace water & residual etchant. Heat seams with heatgun, displace any remaining water or solvent.
-- 2 coats POR15 as primer (used semi-gloss black)
-- 2 coats POR "chassis black" as topcoat.
Very time consuming, but super-durable. I have had this paint combination on my truck's receiver hitch for over a year now. No fading, 100% perfect adhesion, and I can tap it with a hammer and the POR paint will not even chip!
Some have reported adhesion problems with POR paints, but it is 100% to do with preparation (or I should say, "inadequate" preparation.