How can you remove a submandibular (under the tongue) salivary stone at home?

You can't: Some salivary stone are a hard calcified ball or can be a soft plug. They both will limit the passage of saliva thru the duct under the tongue causing distention, pain, and limited movement. They sometimes pass thru the opening but often need to be surgically removed by oral surgeon. Trying to manipulate it can cause self injury. Seek help.