The danger of using such items
is the possibility of cross-contamination with your clothes, the place where you perform Namaz, which may result in the Namaz not being accepted. Moreover, such brushes are used in the confectionery industry, which means that you can get some of the najas with your food, so you should be careful when choosing tools.
To protect yourself from using such things, you need to pay attention to the type of bristles used in the brushes. The websites of manufacturers and distributors usually contain this information.
When it comes to painting brushes, pig hair brushes are usually used for oil painting.
Be careful and think about it every time you want to buy a particular product, because Halal is not only about food, it is also about other items that surround us every day: make every effort to protect yourself from the forbidden in all aspects of this life.