How do I strip quotes?

When you need to remove the quotes on a STRING token, you must use an action to alter the text or emit a token with the right text.

STRING: '\"' CHARS '\"' {setText(getText().substring(1, getText().length()-1));} ;

Some tokens are easy:

ESC : '\\' 'n' {setText("\n");} ;

Note, however that this sets the text for the entire token to be returned from the lexer. If another token references this token then it will still get just the text matched for this rule.