Delet Plug-ins: For Good...

So I've downloaded a handful of plugins lately-some demo versions, some not. Ever since I;ve made these plugins accessible in my MPC software, the software seems to crash much more frequently than before (which was already too frequently- but hey, they do seem to be improving the software overall).

Anyways, I'm not really using any of these new plugins now, and I'm hoping that if I eliminate them, the frequent crashing will stop. Problem is, I don't really know how. I've tried to throwing the application folders for those plugins in the trash, but they still end up appearing as options in my MPC software, even after scanning plugins again.

Can someone tell me a clear, step by step way to get rid of my unwanted plugins permanently?
I have a Macbook Pro and I'm running the 1.6 MPC software.

Thanks!

I mean "Delete" of course, not "Delet"

You should be able to deactivate them via plugin manager in MPC software.

Oh and to really remove them, remove the plugins from
/Library/Audio/Plug-Ins/Components
/Library/Audio/Plug-Ins/VST
folders