4.2
Lift the black shield forwards as far as it will go.
Clean the upper heater, especially the aperture, with a gentle rotary
action, e.g. using an alcohol-moistened wipe (preferably 70 % alco-
hol; e.g. from Reflotron Clean and Check).
A cotton bud moistened with water can also be used. In this case
wipe dry with a dry cotton bud. Then check to see that no strands of
cotton wool have been left behind.