focus lens issues

[xian_crigler]

ok, so second post here.
i have fairly new OMTech (Orion Motor Tech) black and red 80W co2 laser. we bought new at the end of last year.
i am currently experiencing reduced cutting power and some image ghosting.
all mirrors have been aligned and cleaned and the bed has been leveled.

we currently cut 1/8" and 1/4" Baltic birch ply, using a setting of 18/60% on the 1/4" and 14/75% for the 1/4"

but when inspecting the focus lens i noticed a white film on the upper(flat) surface of the lens. i have attached pictures.
the film was difficult to remove. the was not present when we first got the unit.

please help, reduced cutting power and the ghosting are still an issue. what am i missing?

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