[rotorwrench]

If the shocks were service with some form of mineral oil then they may be flushable with mineral spirits to clean out the old and renew the fluid. If they had glycerin or castor oil then alcohol may be the only thing they can be flushed with. Those old fluids can deteriorate and turn into goo. If they don't respond to that then they should be disassembled and properly cleaned & inspected. Maybe they are still usable and maybe they are not. It's kind of a crap shoot in that respect.

Some new ones are sealed but that worries me from a service standpoint. Nothing lasts forever. The ones made by Stipe are the best but they are expensive if you can get them. There are also conversions available to use conventional piston type shock absorbers. They are more affordable but rather invasive to the front axle beam. I don't like drilling holes in the axles.