What can i do to get gum off my dentures?

Adhesive?: By "gum", do you mean that sticky, gooey denture adhesive (glue) you put inside the denture to make it less loose? If you have to put lots of it, you may need a new denture, or at least a procedure called "reline" to fill in the gap with more sturdy material than the denture glue. If the fit is fine but you want to know the best way to remove it, a special denture brush ; spray is the best.

Carefully: You can use vinegar gently wiping the gum off but not with a tooth brush. Try orange solvents as they dissolve organic materials.