Your tongue can go from being pink to yellow to grey. It may be due an infection or disease. It is necessary to clean tongue on a regular basis with a tongue cleaner.
Various types of nasty bacteria reside in our digestive system. They pass through the anus. Thus anus is without a doubt one of the dirtiest parts of the body.
Your nose is one of the dirtiest parts of the body. Scratching or fingering your nose may even develop nasal infections.