The disclosure provides apparatus and methods of use pertaining to disposable bucket liners for storing solid or liquid content. One embodiment provides a flexible bag configured to conform to an interior of a common painting bucket and overlap an open top end of the bucket so as to provide stability for the bag and protection for the bucket. The bag includes a reusable closing member that allows the bag to be removed from the bucket and stored to facilitate repeated use before disposal. Other embodiments are also disclosed.