And taking him aside from the crowd privately, he put his fingers into his ears, and after spitting touched his tongue.
Mark 7:33

Human saliva contains enzymes that promote healing, but that is clearly not what is happening in these instances. Jewish folklore believed that the saliva of a firstborn son had healing power. I doubt that is relevant either, but I don't have another explanation.

Why did he take the man away from the crowd? Perhaps to give the man room to hear clearly, a metaphor of distancing oneself from the world in order to hear God?

It's a very odd episode.