Please help with spitting!

My son is 31 months and he’s been spitting everywhere, he tends to rub it in too. He’s been spitting on the sofa, dining table, windows and other places around the house. It’s constant and I have offered him chew toys he bites into them then throw it on the floor and continues to spit. He’s been doing it all day long. How can I make him stop? I give him alternatives but he doesn’t enjoy them. He normally bites his toys or has something in his mouth most of the time. He does tend to put everything into his mouth. I’m so tired of asking him to stop because he doesn’t even acknowledge me. If I move him away - he runs back and continues to spit. All advice will be appreciated x