Whether a paint brush can still be used after it hardens depends on the degree and cause of its hardening.
If the brush is only slightly hardened due to drying, and the bristles are not seriously damaged or deformed, then with proper cleaning and softening treatment, the brush is likely to regain its original softness and use effect. When cleaning, you can choose the appropriate cleaner according to the material of the brush and the type of paint, such as warm water, soapy water, washing powder water or a specific solvent, and gently rub the bristles to remove stains and hardening substances.
However, if the brush is severely hardened and the bristles have been deformed, cracked or fallen off, then even after cleaning and softening treatment, its use effect may be greatly reduced. In this case, it is recommended to replace the paint brush with a new one to ensure the quality of the coating.
Therefore, for hardened paint brushes, it is recommended to clean and soften them first, and then evaluate their state after recovery. If the brush recovers well, you can continue to use it; If the recovery effect is not good, it is recommended to replace with a new brush.