How do i delete VBOs?

I am generating, modifying and deleting meshes at runtime. And the VBO total count never drops down. I was playing around a little and came up to 30k VBOs, even though i had ~70 draw calls at that time.

Edit: anyone that got a clue? is VBO total allocated VBOs on vRAM or is it just the total VBOs that has existed throughout the lifetime of the program?