Jim Hall wrote:
I've been using wet/dry sandpaper. It's a tedious/time consuming job
and seems to wear out the paper fairly fast. I see Norton has a
flattening stone. I wonderthe y're more efficient. Any suggestions
on how best to get this job done? Thanks..

I flatten my 220 grit coarse stone on one of those. The coarse stone is
then used to flatten the finer stones.

For quickie flattenings of my 4000 and 8000 stones, use I'll my diamond
plates if the coarse waterstone isn't handy. Just like sharpening,
I've found flattening to be easier if done often, before major work is
necessary.