Cleaning the inside of the watch glass

In this article we will see how to clean the glass of our watch inside when we notice that by the evaporation of the oils of the module it is fogged.

For a few months now, I had noticed that the glass in my Wenger Roadster was always dirty. Although I was cleaning it, it was the last few weeks that I noticed that the "mist" inside the watch was still there.

Possible causes of fogged glass

Studying the problem, I can only think of three possible causes that could produce this effect on our watch glass.

• Water filtration through one of the seals inside the watch. This cause is ruled out, since it has not been wet for a long time, besides the "fog" is very uniform
• Evaporation of the oils that lubricate the different parts of the module
• Vapours from the battery

In short, we must open the watch case to confirm the cause of the fogging on the inside of the glass.

Confirming the cause of the glass fogging

We open the watch case carefully to avoid scratching the back of the watch case with the jaxa key.

Once the watch has been opened, with the help of the magnifying glass, we check that there are no traces of water on the inside of the case, module or crown post.

Obviously, in my case, as I explained earlier, the watch has not been wet for a long time, so there is no trace of water or traces of rust.

We also checked the battery, and it is in perfect condition, with no apparent leaks that could be caused by the vapours that dirty the glass.

To better observe any possible water filtration, rust residues or leaks from a battery, we proceed to dismantle the stem and thus we can extract the Ronda 515 movement from the box.

In the case of the Ronda 515 movement, in order to be able to release the stem of the watch and take out the movement, we must look at the small push-button on top of the arrow marked on the module (not to be confused with the hole where the arrow is pointing, it is the push-button above this hole)

With the help of the tweezers, we press the button and remove the stem from the watch without any problem.

Removal of the Ronda 515 module from the watch case

With the loose stem out of the watch, we proceed to remove the Ronda 515 module from the case.

Take advantage of this to cover the module to avoid dust accumulation on the dial and hands.

We check the case and indeed, there is no trace of water or rust. The battery in the module is also correct and without apparent leaks.

In summary, I think the dirt on the inside of the glass is due to the evaporation of some lubricating oil from the module.

We proceed to clean the inside of the watch glass with a microfiber cloth to avoid leaving hairs on the glass. We will check in the light that no dirt remains on the glass.

Before reassembling the module inside the case, we take advantage of the opportunity to blow on the inside of the glass with a cleaning bulb and clean it as much as possible. In this way we avoid that once the watch is reassembled and closed, we see that there are traces of dust stuck to the glass on the inside.

We also blow with the pear on the day and the needles so that no dust remains on them.

We place the module back inside the watch case and check that there is no dust on the glass, dial or hands.

We take advantage of the fact that we have opened the watch to check that the rubber seal of the back cover is in good condition and we apply a layer of silicone grease on it to extend its life and improve its waterproofing.

Once the greased rear seal is in place of the box, we proceed to close the rear cover again with the jax key.

Once the watch is closed, we check that the glass is perfectly clean and the "mist" that made it difficult to see the dial has disappeared.

Let's enjoy the watch again!