Keeping your lens clean is critical, dirty lenses can result in poor marking and engraving capabilities.
You should check your lens at least once a week to insure it's clean. If you are working with rubber or wood, Trotec recommends checking it daily.
Only clean the lens if it is dirty, as excessive cleaning can shorten the life of the lens.
The oils in your skin will damage the lens coating so never handle the lens with your bare fingers.
Always use a proper lens wipe or cotton swab with industrial optic cleaning fluid. Cleaning fluid from a camera store or eyeglass shop will contain water which will harm the lens coating.
Important: Special care should be taken when cleaning a broken lens, broken lenses should always be handled and disposed of in a responsible manner.