トラブルシューティング4I left it for a while and it was moldy!
From "Leather in Japan No. 4" published in 2011
Once the mold is removed from the shoes
The storage environment also improves
When I took my shoes out of the shoe box for the first time in a while, I found a faint whitish substance... I thought it was dust, but it turned out to be mold. Such things happen often. When mold grows, the only thing to do is to remove it. Mold often takes root in leather, so wiping it off is not enough; you must use an alcohol sanitizer to remove the fungus itself. It is necessary to remove the fungus itself by using alcohol sanitizer, etc. Let's wipe off the fungus patiently using the sanitizer.
In addition, it is not enough to simply remove mold from shoes. The problem is the environment in which the mold grows, and if the environment in which the shoes are stored, such as high humidity and poor ventilation, is not improved, the mold will grow again. Let's try to remove mold from shoes and at the same time improve the ventilation of clogs and the entrance.
Leather shoes with a faint white mold on the surface. At first glance, it looks like dust, but the mold has taken root in the leather and cannot be removed by simply rubbing the surface.
Mold lurks between the sole and the bottom side.
To eradicate it, peel off the sole and wash the whole shoe.
When Brass receives a shoe with moldy soles for maintenance, it peels off the sole and washes the entire shoe. This is because mold often grows between the sole and the underside, and this method is the best way to eradicate the mold. If the mold is deep-seated, then again, ask a specialist.