T shirts like to absorb a lot of valuable wax, but when done, boil some water and drop it in to clean it up.. it will retain some wax, but you will get most of the crud off/out, and that will allow you to use it for the next straining job, and you will lose less wax from absorption.
I do this with the cheesecloth I strain with as well.. I layer the filter, .. window screen, cheese cloth, T shirt, that way each of them traps some gunk without plugging any of them up completely..