Alllll of my horses have rain rot. My vet suggested dabbing with chlorhexidine, then gently brushing away the loosened scabs. Has anybody ever done this?

We always used Iodine/water mixture in a spray bottle. It works well but can be messy. If your vet suggested Chlorhexidine it seems to be used as the same, disinfectant/ antiseptic. 

Yup, for the extensive cases, we scrub with diluted chlorhexadine. Works like a champ. 

You do dilute it? Do you apply daily?

my vet hasn't responded yet...

I dilute it maybe 50/50 because I'm weird and paranoid. Another friend doesn't dilute at all. 

I usually will scrub with chlorahex maybe every other day because I want to give the healing good tissue a fighting chance. No basis in science, just me. It usually doesn't take but once or twice to clear it up good enough to heal on it's own. 

I just use a mixture of clorox water.  Just enough clorox that you can smell it then put on with a wet rag.

Yesterday we used VERY diluted chlorhexidine. Today we used full strength (2%). Im hoping to have it cleared up by Monday because rain starts again on Tuesday. I just bought new waterproof breathable rain sheets but I want it cleared up before I cover them.