Well technically, cyanide gas is heavier than air so if we fill the bottom of an old open pit mine with the stuff gravel trucks or iron ore trains could easily park by the edge and dump loads of kikes into the bottom of this massive hole.
Then we'll cover it with gravel and sand to let it settle, fill up with more gravel and sand. Then leave it as is, let the birds and local wildlife shit on the rocks until various organic materials starts to grow, in a couple of centuries we'll have a nice forest. In a couple of thousand years future generations will have access to jew oil for their Wolkswagen cars. 👌