My son is also 4 and nonverbal. He would also bit on his shirt collar and even his sleeve sometimes. We tried a few chew toys but nothing. Then he started eating non edible items such as crayons, paper, parts of pencils, etc.... even a whole pencil color!!

We noticed he also liked chewing on the straw when we would give him a cup and he would chew on it for loong periods. There after when ever we saw him chew on something he wasn't supposed to, we would give him a straw and he slowly stopped putting most other items in his mouth.

Thank you both for the information!

It comes and goes with us. It can be a vitamin deficiency. Our son stopped chewing and recently started chewing holes through his gloves. OT suggested crunchy and chewy sensory diet and chewy toy. He will not wear it around neck or clipped. We try to make sure he gets input in different ways which seems to help. I saw chewy wrist bands on Funandfunction website. I might order a set because it is cloth.

This is a tough one and not easily fixable. When a child does this it is most often a sensory sort of Stim. For my daughter we tried the chew necklaces and things of that nature with limited success. We started to get her lower cut shirts and shirts not long sleeve and it helped. I think in the end she basically grew out of it after use redirecting for so long. This phase for us was almost a year so it was nothing that went away quickly.