The way to clean the MAF is take it off and use carb cleaner, don't ever poke the sensors with anything they are fragile, watch your eyes as the carb cleaner sprays give a big blast, and it stings like buggery in your eyes!!
After the clean just shake dry, then after putting back on car, pull the violet fuse from the fusebox near battery for a minute, it is a 2 or 3 amp fuse, may be marked KAM, this will reset the ecu and it will relearn the best running settings so may be a bit iffy for a mile or two, but just drive as normal.
I would do this before thinking about the lambda, which if buggered can't be cleaned/fixed, but a mot emissions read out will tell you if it is ok or not.
tabetha