How to tell my roommates without hurting feelings?

You need to assign some general duties. Kids often are used to their moms cleaning up after them. These girls need to learn that maid service has been cut off. You are very kind. Don't do their cleanups though.

Maybe a little sign on the wall saying if you dirty a dish you wash it. Something subtle? If that fails, get together and talk. They probably don't know it's their responsibility.

OR, you two could dirty ALL of the dishes, and leave them in the sink. :-)

Man, when I was in college we shared bathroom and kitchen duties, and I can tell you that if anyone failed to do their job, the rest of the suite had plenty to say.

If I were you, I would take a large trash bag into the Kitchen and fill it with all of their dirty utensils and left over food that is messing up the Kitchen and set it in a place that would be in their way so that they can not ignore it. I would also scour the sink and wipe the counter tops for sanitary reasons.

just be like so whos gonna do the dishes ? lol. or you and your roomate can just complain about it to eachother infront of them and be like wow this smells, or something like that so they hear you and theyll get the hint

your too kind. just tell them. if they live with you then they gotta do there dishes... because its what they made. tell them what ever you do you clean up. its part of being roomates.