A letter of protest is an informal procedure that allows third parties to bring to the attention of the USPTO evidence bearing on the registrability of a mark. The letter is filed with the Director of Trademarks and if the Director is persuaded by the evidence, the letter will be accepted and the evidence forwarded to the examining attorney. Only the evidence is forwarded to the examining attorney. Accordingly, it is important to keep any legal argument in a letter of protest to a minimum. This also has the effect of keeping costs down with respect to the preparation of the letter of protest. If the examining attorney finds the evidence persuasive and issues an registration refusal based on the evidence, it can be a cost effective tool to keep the principal register clear of a concerning mark.