The surface of friction stay should be cleared often, but not use the strongly corrosive solvent.
Please use the relative tool to fix the loosed screw.
All moving and fricting parts of the friction stay , should use lubricationg oil or other lubricant , only the place of the sliding plate and track is not included , because of their own-lubrication.
If the window could not use conviniently , or the sealing property is not good and so on , please kindly consult to our engineers before and taking the related steps.