On the hihat I found this to be very helpful (the coins work really well, specially when the hihat is played closed) (the entire thread is here):
These have all worked for me, in increasing order of deperation (most deperate acts at the bottom):
Throw some spare change or a set of keys or some small nuts and bolts in the space between the two hi-hat cymbals. I much prefer this to using tape. The extra weight seems to deaden the cymbal a little without losing the texture, and the keys or coins jumping around inside a little sound good.
Try using the bottom hi-hat on the top -- sometimes the bottom cymbal is heavier and will be less piercing, especially if it has holes cut in it.
Use larger/heavier hi-hats. 15" is not excessive, and we keep a couple pairs around for emergencies. They will be lower in pitch and will probably not be as loud. I have recorded several drummers who use 16" crash or cut-down ride cymbals for hi-hats for this reason.
See if the drummer can raise his hi-hats a few inches. This gets them a little farther away from the snare drum mic, where a lot of bleed comes from. It also shortens his hi-hat stroke, so there is likely to be less energy on each hit, and changes the angle slightly so the cymbal is hit more on the edge than on the top -- which also softens the sound.
Use flimsier, trashier-sounding hi-hats. Camber, CB, Solar, Ufip, Zilco, Meinl, Bosphoros, Pulse, Wuhan -- anything other than Sabian, Zildjian or Paiste. They may only last a day, but they only cost 30 bucks. If you can bend it with your bare hands, you've found a winner.
Once the material has been recorded, you're shit out of luck. I have been able to tame hi-hat bleed in snare drum and rack tom tracks using a de-esser (DBX162, DBX900 module, Dyna-mite, BSS DPR 402, Orange County Stressor), but it isn't preferred to making a good recording initially. If you can tidy the snare and rack tom tracks that way, the overheads may not be too overbearing after all.
I would not recommend using a gate, as the gate, when open, will send the hi-hat blazing through, and you'll get the worst of both worlds: Choppy and piercing.
best,
steve albini
Electrical Audio
sa at electrical dot com
www.electrical.com