the oil put into the clutch release bearing cups, the oil in the bevel gear case and the oil in the final drives, each can potentially leak into the case and accumulate enough to oil the clutches.
Not real likely in the short run, but along with moisture/water accumulation to float it up a bit, over time it can really mess one up.
Have you adjusted the steering clutch linkage so that you have free travel as the manual shows? If you have free travel you might try washing with kerosene or diesel again or just pull them and get on with replacing them. There is a limit to the amount of wear before the drum hits and the springs can no longer compress the disks.