Not a job I have done very often, as mentioned in other discussions I like to keep my fork legs very clean to prevent seal problems, and have had several bikes do over 50,000 miles without leaking. But if I am servicing the forks then I remove the legs and give the whole things a good clean, how often do you see a bike with rusty fork legs above the bottom yolk and you can be sure the legs are rusty under the triple clamps. Bite the bullet, pull it to bits and why not Greece the head races as they probably need it.