take the car for a blast on a (privite road) and kick its hole,

i wasnt on about the cleaner, the bit about taking it for a blast, ive done this lots of times to get through emissions on newer cars.

if you make a small air leak the emissions will come down, too much the car will stall

dipstick was just an example you could use breathers, oil cap etc.... saves you messing about with the co adjuster without the correct equipment.