When representing the purchaser, the broker should never by any chance make a written offer for the property. If, for example, a purchaser's broker should write to the owner's broker that his client is willing to give $350,000 for a certain property, the owner's man may show that letter to other prospective purchasers. Such a letter is definite proof that some one else wants the property and fixes a minimum valuation. "If Smith, the well-known broker - he's a shrewd appraiser - offers in writing to give $350,000 for a client, you can see how valuable the parcel is," may be the use that will be made of the offer. This simply places the purchaser in a position where his offer can be made a boomerang. If, on the other hand, the offer is made orally, the owner's broker has nothing to show, and his statement of the offer, in the absence of proof, might be looked upon as insincere.