Dyeing wash rags in lurid (or at least useful) colors?
I have a habit of using cheap bar towels (or, more precisely, towels from Target intended for drying cars, which are about 18" by 24" white terry cloth and available in packs of 24 for about $10, so there's not much expense in having lots of them) for drying dishes and cleaning kitchen counters and dusting and other similar sorts of things.
A year or two ago, Suzi happened to wash some of them in the same load as a large red rug. This produced an obvious-in-retrospect result: A couple of dozen pink towels. This turned out to be an excellent occurrence, as now we have a second set of towels that can be used for the extra-cruddy tasks (like washing the floor) without concern that they'll end up mixed back into the set of towels used for drying the dishes.
However, cheap towels wear out, and there are never enough of the pink towels to make up a laundry load, so I'd like some more of the pink towels. Or, more precisely, I'd like to take some of the dirtier stained towels from the white set, and add them to the pink set.
Thus, my question: What's a good way to die these? I don't entirely expect the rug trick to work twice, as that was the first time it had been washed. I'd like something that would die the towels a distinctive non-white color that would last through lots of washings (although I don't care if it fades a bit), and won't bleed out of them when I soak them in hot water or cleaners. Any suggestions? Is cheap supermarket RIT dye sufficient for this, or will I end up with towels that will drip dye on everything I try to clean with them?