FlytrapCare Carnivorous Plant Forums

Personally, I've never tried it (I'm allergic to coconut and didn't want to chance it) but you should be able to find instructions here or on Google. The major problem with coir is salt. What I'd try to do is to rinse it many times with tap water to get rid of the salt and then a couple of times with distilled water to get rid of the TDS from the tap water. But look for other ideas - like I said, I haven't tried it myself.

First thing that I think I'd do with the coir would be to soak it and get a baseline of the TDS in it. Compare that with the TDS of your tap water. If the coir's TDS is higher (most likely it will be much higher) then use the tap water to rinse with until the TDS of the "coir water" gets down to the tap water's measurement.
*Then* switch over to distilled or rain water for rinsing to get the TDS down from the tap water level. Does that make sense???