Finish the following sentence with the best choice: How to soften hard paint?

Choices:
- Add a mixture of turpentine or thinner to the paint  jar and try to stir it soft quickly
- Add a mixture of turpentine or thinner to the paint and let it set then try to stir it soft

Answer:
Add a mixture of turpentine or thinner to the paint and let it set then try to stir it soft