Can't vouch for the Epson (not epsom; that's salts) inks specifically, but the inkjet iron-on transfers manage to survive laundering pretty well when printed on cotton. It's possible that the wax used in the transfer paper helps seal the dyes into the fabric... or it may just be that most dye-based inks are adequately colorfast on natural fibers. If you're printed on an artificial fiber... dyes don't stick very well to them unless mixed into the plastic before the thread is pulled, even with a mordant added. Similarly if you used a pigment ink rather than a dye-based ink; pigments are great on paper but I'm not sure they'd hold up to washing. In those cases, the best suggestion I can come up with is to try a fixative/water-resistant spray, available from art supply stores. This is basically a kind of varnish, and it *might* soak into the fabric well enough to glue the dye or pigment to the fabric. It will probably make the fabric a bit stiff as well. Actually, a good art store may be able to offer better suggestions. They're used to people trying to do weird things with their supplies, and may have run into this question before. Other than that... Print onto a few handkerchiefs or other scraps of fabric similar to what you're trying to preserve, and run some experiments. Either you'll find a solution, or you'll have to go back to a different printing technique. Good luck!