My sister always goes and uses my things without permission. At first, I was like, it's okay, but try to ask me next time. But it's become constant. She recently used my room spray (I know it's not a big deal), and it was expensive. She sprayed about 5x more than what was necessary and now my room smells sickening. Along with this, she got grease all over my desk and doorknob, ruining my computer in the process. I've brought this up to her, and she's denied it, saying she doesn't even know where the room spray is. However, I've shown her where to I keep it numerous times. Maybe this was my fault, but I don't appreciate this anyway. What should do? My parents won't believe me, but she's done this before, even admitting and apologizing to me. This is kind of just the first step. What if my personal (like things that are actually important to me) belongings are next? There are just some things I don't want her touching.