In principle, mental hygiene is no different from physical hygiene. You need a soap, you need a means of applying the soap and you need consistency.
A soap’s function is to remove dirt while also nourishing the skin by replenishing lost nutrients. The ideal soap is natural and has nutrients that are similar to the body’s. Using a bad soap causes long term damage even if it appears to clean. The ideal soap represents truth. The mind can only be cleaned with truth since truth is what the mind was designed to contain and feed on, the same way our bodies were designed to feed only on natural and not synthetic substances.
I love applying this soap from Apostle Paul to my mind,
“Fix your thoughts on what is true, and honorable, and right, and pure, and lovely, and admirable. Think about things that are excellent and worthy of praise.”
This thought makes it easy to identify thoughts that are not clean. Applying this soap again and again removes garbage thoughts and reveals beauty, potential, truth and purity within and keeps the mind free of trash. I know I need cleaning when I start to think thoughts that in my sober moments, I know are untrue and unwholesome. And just as dirt corrupts the underlying surface with time, unwholesome thoughts corrupt the mind when persisted in.
Mental hygiene requires practice. More than ever, we need practices that allow for mental stillness. Solitude is an indispensable practice for periodic mental cleansing. Periodically disconnecting from the external including social media and connecting with your interior space helps. Cleaning and other simple physical activities are also rich practices. They help to shut down mental chatter and make us more receptive to inspiration. While moving your limbs in the process of lifting physical dirt, your mind can become still enough for you to uncover insights within. The kingdom of God is within you after all. And once your mind is quiet, you can observe your thoughts. If you do not observe your thoughts, you cannot begin to clean your mind anymore than a cleaner can clean a room without being present. Cleaning requires presence and presence is a cleaner.
We can return our minds to truth in the various areas of our lives and society. Any thought or opinion that you have about anything at all can be based on truth or not. Thoughts that are not based on truth are much more harmful to you and to others than leaving your body unwashed for weeks. Thoughts about race and police brutality for example, need a lot of cleaning. Will violence against police truly arrest police brutality? What does screaming Black Lives Matter achieve if black lives do not matter to blacks? I believe we need mental cleaning when our thoughts on an issue are the same as the majority of people, because they are often untruth. But what is truth and where do you find it?