A number of people have asked me for a quick tutorial on using dishwasher gel for discharging, or removing dye from fabric. I'm no expert but I'll tell you what I have learned through experience.
My "Law & Order" law degree dictates that I give all the inane and obvious warnings up front - Don't drink dishwasher gel. Don't make it into meatloaf and don't use it to cure crabs. Being a carbon based life form myself, chlorine bothers me so I work outdoors and wear gloves and glasses. Duh. This stuff will kill you as quickly as most anything else under your kitchen sink. If anyone chooses to disregard common sense (so what else is new?) the gene pool thanks you for getting out.
Cheepo store brands work as well as the more expensive stuff but because they are thinner, I find the store brands easier to work with. I started out by putting the gel in a plastic hair color applicator bottle and squeezing it out where ever. On the last batch (pictures above) I painted the gel on with a fat brush which later died an early death because I forgot to clean it *
The gel is harder to see once you start moving it around with a brush. Putting gel on wet fabric will give a different result than on dry. I like the creeping halos that you get with damp fabric and used a spray bottle of water to keep things damp as I worked. Half the fun of discharging is not knowing what's happening under the gel as time passes. Time? Anywhere from 15 minutes to an hour or more depending on too many things to go into. Remember, it's voodoo.
If you are deeply in love with the fabric (sick puppies, alla ya!) do some testing on a little piece of it and take notes. In the batch pictured above, I was working with PFD cottons that had been dyed and overdyed to death disastrously so the color came off in layers. I HAVE NOT SUCCESSFULLY DISCHARGED OTHER FABRICS! Warning - I did eat some cool holes in a silk velvet scarf a while back.
Some Procion MX dyes come away quicker and more completely than others. Some commercial fabrics discharge well while others seem impervious to the bleach in the gel. And finally, get a bottle of Anti-chlor or Chlor-out from the pet section in the grocery store for the final rinse. It's cheaper than the gel and it chemically cancels the chlorine. If you don't stop the bleaching action of the gel your fabric will ultimately resemble old underwear - gray & holey. Vinegar to cancel chlorine? No. Don't argue. The folks from the dyers list have already bitch-slapped sense into my head over this issue. Any questions? Feel free to ask.