Glitch is pretty well known.

You can use it on any spot with the slightest corner.
You take a fire, throw it on a corner ( I believe in the case of the video, it's the boxes in upper, how they aren't even with the wall) Then throw the smoke at any height in the same corner.

In the Revolver update they thought they patched it but it didn't work out perfectly, before it didn't have to be on a corner, just the side of a wall.

It's not a glitch, when a smoke lands on top of a fire, there's a gap left beneath it. This is just a one way smoke and it's pretty easy to pre-fire. Not to mention, it costs $900 to use it so it's way too expensive. Good find though

It's a one way smoke, not a glitch.

Also, this is only really helpful if there is only one player on CT playing B site. Any more than one and this would just get in the way

Either way, it's a nice one way. I know most of the others on D2.

I've seen this so many times now haha, but yeah, it's good to post stuff like this because not everyone knows about it.