If you sometimes clean paint off your skin with paint thinner or turpentine, could this have adverse effects? like carcinogenic, mutagenic, reprotoxic etc? not at all or only when you clean your skin like that regularly?

It is not carcinogenic but frequent exposure is not good for your health. You can read more info from this link: https://healthfully.com/dangers-paint-thinner-8249573.html

Although I agree with Dr. Le that this is not carcinogenic or mutagenic, please have adequate ventilation due to potential fume exposure. There is an entity called "Painter's Encephalopathy" resulting in chronic cognitive dysfunction due to inhalation of these chemical vapors.