Are the seals good enough to hold kerosene ?
If so put them together . Mount and compress them . While compressed , fill with kerosene . Then release and cap .
Ride around for a few days , letting the kerosene work its magic of cleaning parts .
It should provide enough lube for that short period .
Then drain , tear the forks apart , clean and 'lube' appropriately .
Short of that^ , I'd still cap an end and fill with something stout enough and let it soak for a few days . Might help if you could somehow shake the tubes around every once in a while , during the soak .