Take it apart, put the plastics in a soap and water solution. Clean the electronics with compressed air and a small toothbrush with isotope Isopropyl alcohol were needed.
Any yellowing of the plastics you can use peroxide with a UV light.
Seriously? That's almost grandma saying "playbox" level. And do you not know what NES is an abbreviation of? Its "Nintendo entertainment system", which means you wrote "Nintendo Nintendo entertainment system".
You're right about the Nintendo stuff, but could you please not mention grandma's playbox ever again in posts where the topic is about insinuating filthy vaginas.
Turn it off, remove the battery, and put it in the dishwasher on a gentle setting. Then wait a week or two for it to fully dry before powering on again