Swingman wrote:
"B A R R Y" wrote
I've found flattening to be easier if done often, before major work is
necessary.
I've finally learned to deal with it ... thank gawd for the WS300! 
What a difference it's made in keeping chisels and plane irons sharp without
fuss/muss and "waterstone" mess all over the bench/shop.
(Just had to throw that in) ... mainly because it so damn true!
I have a Tormek. I only usually use a 4000/8000, once backs are
flattened. Very little mess, as they only need a spritz. I flatten in
the kitchen sink.