When we thrive not to remember something, say red colour, our brain continues to see red colour ever where in efforts to not remember it.
So if I try not to think I have to either keep my attention in a blank thought; Which seems not possible. Or else i can opt to sleep, where definitely the thoughts cannot be witnessed with consciousness.
And the last thing, which seems to me the only way is, just observe the thoughts and let them fade. It makes no difference that what and how many thoughts are coming up until it gets no attention in consciousness way