To store comic books long term, it's essential to keep them in a climate-controlled room. Use plastic bags or sleeves specifically designed for comics. And don't forget to label and organize them properly so you can easily find what you're looking for later.
For long-term storage of comic books, first make sure the environment is stable in terms of temperature and humidity. Then, keep them upright in archival-quality boxes and avoid stacking them too tightly. Also, handle them with clean hands to prevent dirt and oils from getting on the pages.