Brown Jelly is highly infectious. I would siphon out as much of it as you possibly can, and then maybe give all your corals an iodine dip to be safe.
After that, I would keep an eye on them very closely for a couple of weeks. Pick them up and physically examine them, including the base of the coral where they are attached to the skeleton/rock. You may not physically see the brown jelly, but if you see any tissue sloughing off, then you should take immediate action.
When my Goniopora got brown jelly, I couldn't physically see the infection but it was losing tissue rapidly. I was advised to give the coral an iodine dip twice a day for 3-4 days depending on whether or not the infection was coming back or if the coral was still shedding tissue.
Mine was pretty persistant and I dipped it for about a week straight before things started to look normal again. I also doubled the dosage of iodine and upped the time I dipped it by about ten minutes.
I would not do that unless your corals are infected though. One 10 minute Iodine dip should be enough to kill anything that may have possibly gotten on them and will hopefully prevent them from contracting the disease.