We have a short writeup on our website with information on how to clean liners www.restek.com/en/frequently-asked-questions-faqs/frequently-asked-questions-GC-accessories/#sec06 An abbreviated version is below, but there are more details in the full article. To clean a liner with no visible deposits or discoloration, it is best to rinse the inside with the following solvents in sequence: methanol, then methylene chloride, then hexane. Use a cotton swab or pipe cleaner to gently scrub the inner surface of the liner, but be very careful not to scratch the liner and thereby remove the deactivation layer. If deposits are visible or the liner is discolored, it may be necessary to ultrasonicate the liner in methanol, then methylene chloride, and then hexane.