Before attempting to clean a watch, it is advisable to become thoroughly acquainted with its mechanism. First remove the hands and dial, then unscrew the balance cock and take out the balance, unpinning the hairspring if necessary, and notice how far through the stud it comes, so that it may be properly replaced when putting together again. Then let down the mainspring by lowering the click screw under the pillar plate and putting a key on the square of the barrel arbor. Take out the barrel and bar, also the pillar pins, raise the plate gently, and with a pair of tweezers remove the lever; then take off the top plate and remove all wheels, etc. Place all the parts, except the barrel and fusee, in benzine. Take out and brush clean with a soft watch brush and a trace of dry chalk. Brush clean the fusee, take off the barrel cover, and oil the mainspring. With a watch peg sharpened to a fine point, clean out the pivot holes. To put together, place all wheels in position on the pillar plate, but not the lever; put on the top plate, and then introduce the lever between the plates and get it into position; then get the top plate down properly and insert the pillar pins.

Put in the barrel and bar, put on the chain by dropping it through the watch in position, and hook the barrel hook in the barrel. With a key on the barrel arbor, wind it all upon the barrel and place the fusee hook in the fusee. Then set up the mainspring half a turn, and wind the chain up on the fusee, being very careful to see that it goes straight. Oil the pivots in the top plate and the balance pivot holes. Put in the balance and repin the hairspring, being careful to get it in beat. To test this, wedge the fourth wheel with tissue paper, and when the balance is at rest the ruby pin should in the lever notch and the lever should stand midway between the banking pins. See that the hairspring lies flat and beats evenly between the curl) pins in the regulator; also see that it does not touch the balance arms or the plate. See that the balance has a little " endshake " in its pivot holes. Oil the bottom pivot holes, and put a little oil on the points of the 'scape-wheel teeth. Do not oil the other wheel teeth or the ruby pin.

Use only the best watch oil.