caddywumpus and mcjnic have talked about this procedure, and Osaka Bop has described it perfectly. I used it on a ride cymbal, worked great. Get some mallets, and roll on the cymbal for 15 minutes. I made a cool exercise out of it, by, doing different dynamics up and down the cymbal. It was fun and did the trick. I'm thinking of buying some new hihats, so, I was wondering if this worked on smaller cymbals. If mcjnic has already done some study on this matter, I would go with his opinion.
Strange thought: if you (Gilnar) try it out on the hihats, you might want to split the hats up. Put the top on a cymbal stand and do the procedure, then, repeat with the bottom hat. If I get a new set of hihats, I'm going to try this. That's me.
Another way, just play those hats! Play 'em all the time.