Tried both of those. Even tried putting soap, vinegar etc in her mouth when she does it, its normally to kids her age or younger. She won't do it if there's older kids around
Time for some serious punishment. Explain what will happen and then when she acts out, follow through. Find the things that are most important to her and take them away and escalate the time/number of things each time she does it.
Sounds like she has learned that the consequences of her actions are worth enduring and will continue to do it until she realized that they aren't. Go nuclear out of the gate and stop it in it's tracks.
She is exhibiting "bullying behavior" and the roots are usually because she feels like she is being bullied somehow and is passing it down to establish a feeling of self control. You need to address that too and get to the root of it. Beyond stopping it, you need to force her to explain 'why' she is doing it and then help her get over it.