Mirrors and lens are very important ports of the machine.Han`s yueming laser installs mirrors and lens made in the USA or Singapore. 
Usually, the focus lens need to be cleared every three or four days.

First, take down the lens barrel .

Second, clean the focus lens with 95% alcohol with cotton sticks.

Third, dry the focus lens with cotton sticks after cleaning it. This step is very import. If the lens working with alochol, maybe it will burned.