Treasure Hunting

There isn’t a whole lot that REALLY bothers me when it comes to pet peeves or annoyances. There are several little things that bug me, but not really much that I get really irritated with. But if there is one thing that I absolutely can’t stand, it would have to be when anyone - child, adult, teenager, etc- picks their nose. Now don’t get me wrong, I did my fair share of gold digging as a kid, but it seriously makes me sick when I see people picking their nose. I don’t mean just a little flick or nose rub, I mean when people are doing some serious treasure hunting.
For anyone that doesn’t know what my job is, I am a mentor for youth in therapeutic foster care that have behavior problems and developmental delays. For the most part, my job consists of me taking them out in the community and doing different activities with them to work on their individual goals and behavior issues. Now I love this job- it is very challenging, yet incredibly rewarding. Knowing that these kids have behavior problems, I should expect to see pretty much everything, and for the most part I do. But there is this one kid that has this "treasure hunting" problem and it’s driving me INSANE!!!! I continuously offer her kleenex and napkins, but she continues to pick and dig and pick and dig. It seriously is making me gag thinking about it. Yuck!
So today was the last straw. I don’t know what I’m going to do now, maybe make her wear nose plugs or something. But here is what happened: We went to the amazing and incredibly skate world and then we decided to go to the park for awhile. It was a little chilly outside, but not too bad. Well when we got back in the car, apparently her nose must have been running or something. She was really going at it, hoping to find some gold and I reached over and got some napkins and told her to use that for her nose. She said "okay thank you". So I thought, problem solved, I’ll just make sure to sanitize the door handle so no booger germs remain. Well problem NOT solved! I took her home and dropped her off, and just as I was getting ready to pull out of the driveway, I looked down at the passanger side seat and there IT was! A nastly slimey snot-ball!! YUCK! SICK! DISGUSTING! GAG! HURL! Oh man I was about to flip a lid! I got out some more napkins and cleaned it all up but I was nauseated and gagging the entire time, as well as many minutes later. This was so gross. It wasn’t a little kid’s booger, which still makes me gag, it was a 15 year old girl’s snot ball!
I don’t know what to do about this, I have tried so many times to tell her she should use kleenex or napkins or something of that nature to wipe her nose because that spreads germs. She never really says anything in response though, I think she just likes it and doesn’t want to stop. Well it really grosses me out big time and I don’t want to see anymore nasty slimey snot-balls in my car or anywhere near me! If anyone has any suggestions to get this kid to stop, please, oh please, be kind enough to share with me!!