Black crusty stuff on rat tail

Question
I have a two year old male rat and he has a bunch of black crusty stuff on his tail.  He seems happy and healthy but I'm not sure what this still is.

Answer
Dear Hannah,

It is impossible for me to know what it looks like without a photo. However, it is normal for a rat to develop a dirty, crusty tail. You should help him to clean it. You can use a soft toothbrush and warm, sudsy water. You can use a mild dish soap or baby shampoo. If it is gross, you won't want to do it all at once. When I did it recently, I rubbed the scales backwards carefully in a few spots and it was enough that it irritated him a bit and he cleaned that part of the tail himself. So that's all I did; I washed a small section and pushed the scales back, and he or maybe his brother took care of it, until the tail was clean.

If it is not dirt, send me a photo so I can help you to figure it out.

Squeaks,

Natasha