And keep the keg parts together with each keg. I put the parts in a hop bag and hang it in the keg while it's full of PBW.
Indeed, I learned that one the hard way. When I bought my 8 used kegs, I later found that one was not a "true" coney keg, and the poppets were slightly different. Fortunatly, I kept all the old poppets and was able to diagnose the reason one of the kegs would not seal at the posts! (of course I already had 5 gallons of beer in it when I found out!)
I guess for now, I will keep up with the same procedure I used when I got all 8 kegs. What I did was something similar to what Lonnie is doing. I took a spare 1/4 hp "sump pump" I had around the house... filled up a sink and keg with PBW, and connected the sump to the gas and liquid posts. Then I turned on the sump and let it pump hot PBW thorugh the tanks for a half hour a piece. It worked great since I had 8 kegs to do and I just swapped each one every half hour or so during the day. Then I re-built each one with new poppits and gaskets.
It seems a bit overkill for just one keg at a time, so I will probably rinse each one as it dies, and then when I get two or three..do the same thing I did when I got them.
Knowing the most critical things to makeing beer is sanitation, sanitation, sanitation, sanitation, good fermentation, and avoid oxidation... my hope to be able to be a bit more lazy may not be advisable!