Is it consider Borer on shabbat to remove cotton balls of hair often found on your clothes ? For example on your suit ? With your hand , not with a brush obviously.
No, this is not considered borer.
The first and most basic condition for the prohibition of borer to apply is that there should be a mixture (taaroves).
In the case of thread balls attached to clothing, this is not a “mixture” — nobody would say that the cotton balls are “mixed up” with the garment.
Rather, the cotton threads are more comparable to feathers or dandruff that lies on top of a garment. It is permitted to remove dandruff by gentle patting, and this involves neither borer nor libbun (because no dirt has penetrated the garment). This will also apply to the cotton balls.