Pea size black scabs on dog's tail

We have found a few of black scabs on our dogs tail this year - first in Feb and second in May 2023 both in different spots on her tail. Just checking if this is normal for dogs or if we should be concerned. As soon as we noticed them from petting her they are very easy to remove, just lightly pinch and pull. It seems like part of the scab is still partially in the skin when we pulled it off but there is no blood just looks like an empty dry hole on her skin. Both scabs look and feel the same just in different places on her tail.

Hello - I'm afraid that I can't visualise what you are describing here - is it possible to post a picture?  I wonder whether you are describing comodones or seborrhoea, for example, or even flea feaces.   None of these are normal but all are common and can be treated.