1, Remove the back cover. On some watches, the cover will pry off using a very small flat-bladed screwdriver or will have screws holding the cover on. On other brands the entire cover will unscrew. Examine the edge of the back cover. If there is one small depression along the edge of the cover then the cover will pry off. If there are screws present, the cover will lift off after the screws are removed. If the cover has a raised edge with flat edges opposite one another then the cover will unscrew.

2, Carefully remove the gasket. Almost all watches will have a rubber-like gasket around the edge of the back cover. Carefully remove the gasket and set it aside for reassembly.

3, Locate the battery. The battery will be a round, shiny, metal pill-shaped object.

4, Remove the battery. If the battery is held with a cover and screw, remove the screw using a very small screwdriver. The head may be Phillips or slotted. Carefully set the screw and cover aside. Remove the battery and set it aside for identification. If the battery is held with a spring clip, pry the battery from under the clip with a small flat-bladed screwdriver. Note very carefully which side of the battery is facing outward and which side of the battery is facing into the watch case prior to removal.

5, Identify the battery. Watch batteries are identified with numbers located on the back of the battery. The numbers are generally 3 or 4 digits such as 323 or 2037. Notice that one side of the battery is marked with a large plus sign. This is the positive side.

6, Purchase the replacement battery. Watch batteries may be purchased in the U.S. in drug stores, discount stores, electronics stores and jewelry stores. The number of the battery ( not the watch model ) is required to purchase the battery. Bring the old battery.

7, Install the new battery. Remove the battery from its protective wrapper and wipe the battery to remove any film or fingerprints. Place the battery into the watch body in exactly the same position with the same side down as the old battery. Put the battery into the clip or replace the cover and screw.

8, Check for operation. Turn the watch over and check to see that the second hand is advancing or that the seconds digital display is advancing, depending on the type of watch.

9, Replace the gasket. Place the gasket onto the cover or into a groove provided for it in the case. Be very careful that the gasket is fully into the groove or around the cover evenly so that no part of the gasket will be pinched when the cover is installed on the watch body.

10, Replace the cover. Be careful not to damage the gasket. The gasket may be impossible to replace if damaged. (Note: this probably will require a special device that you can either purchase yourself or (more likely) pay a watch shop or jeweler to use for you. There will usually be a small fee–around $10.)

A watch requires occasional cleaning and upkeep. There are many places on the watch where dirt, body oils and other greasy particles accumulate, such as between the links on the bracelet, the area joining the case and the bezel, and around the Cyclops lens. On repeated use, you will see clearly such dirt particles on your watch. When such particles are seen, the watch will require a thorough cleaning.

Following these steps to clean your watch:

1, Before you start, make sure the winding crown is tightly screwed onto the case.

2, Washing your hands thoroughly with soap or hand wash so you avoid transferring any dirt or grease.

3, Use lukewarm water to rinse off your watch.

4, Fill a bowl with lukewarm water and ammonia-free mild soap.

5, Apply this soapy water all over your watch using your hands.

6, Now, gently scrub the watch to clean it of all dirt particles. Your old toothbrush can be used as an ideal scrub for this purpose. During scrubbing, submerge the watch and the toothbrush into soapy water at short intervals.

7, Once you are confident that the watch has been cleaned, rinse the watch with lukewarm water.

8, Using a clean and soft cotton cloth, gently pat the watch until dried.

9, Since your cloth may not reach the links on the bracelet, you need to use a blower or hair dryer to remove the excess water from the inner surface of the links.

10, To make your watch completely dry, you can also use a dry towel to remove any remaining moisture.