Complex sentence: Oil paints may require the use of solvents such as mineral spirits or turpentine to thin the paint and clean up; these generally have some level of toxicity and are often found objectionable.
Split into simpler sentences: Oil paints may require the use of solvents such as mineral spirits or turpentine to thin the paint and clean up. These solvents generally have some level of toxicity and are often found objectionable.