Hi Hat Bleed
Hi hat bleed can be a real problem when micing up a drum kit. Here are two techniques I use to minimise it during the mixing stage. Start with the Fabfilter multiband and select the expander option. Set this so it only affects everything above 3kHz, with the fastest attack and a pretty fast release. This starts to get rid of a lot of the hi hats, whilst keeping the natural sound of the snare.
Next add a gate. Fabfilters gate is perfect for snare’s because you can set the range so that it doesn’t completely cut off in between hits, resulting in a choked snare sound. Use a fast attack and play with the hold and release until they keep as much decay of the snare as possible without letting the hi hats creep back it.