WASHINGTON, DCInvestors have been staking out Federal Reserve Chairman Alan Greenspan's home in an effort to gather any clues that Greenspan will institute an increase in the interest rate, neighborhood sources reported Tuesday. 'Right now, Mr. Greenspan is applying a second coat of Turtle Wax to his Lexus,' mutual-fund investor Ted Iger said, as he squatted behind an oak tree. 'Maybe he plans to sell the car before raising lending rates.' Iger said a major household purchase would corroborate theories he has about the microwave box Greenspan's wife carried to the curb Sunday. 