I think you should give her a bath. I have rescued a lot of kittens off the street (4 more this past week) and have had to give them all a bath. They go from icky dirty strays to squeaky clean housecats immediately! In fact, the latest two I caught (Josephine and Edward... below) are scheduled for a bath in about 30 minutes. I gave them their Frontline the other day and wanted to wait for it to do it's job. I'm sure they will love it... well, perhaps not.
The easiest way I have found to give kittens a bath (and the least stressful) is to do it in the tub with my detachable shower nozzle. You can put a small harness on them attached to a leash just in case they escape your grasp and then gently scruff them while washing. If they are really scared I take a wash cloth and drape it over their head and they usually calm down quite a bit.
Go slow and make sure they are at the end of the tub that is opposite the drain so they aren't standing in water. She will be so happy to be clean that I'm sure she will forget that you even gave her one.