have you not heard that WD40 is made with Fish Oil?
If i'm honest, i will admit to having attempted a quick "clean" of a MAF in the past, but only as a last resort, and normally once i already have a replacement either on the bench or on its way, and i have never managed to salvage one yet.
i have never used WD Cod eye Ant Harris Gland 40 to try it, as it does clearly leave a residue, but i have tried many other things in the cupboard, including a purpose made MAF hot wire cleaner that the Yank have been selling/using for years, easily found on Youtube, Fleabay etc etc.
The MAF is an electronic device, as such it will not last forever, and should be considered a service item these days unfortunately.
I know the price of many of them is ridiculous, but if you get the return signal voltage values, it is easy to test when one is letting you down with a multimeter, or if you have it FES or Alfadiag, and if it is found to be failing, i'll put money on you'll end up buying one anyway.
Keep cleaning them if you will, great if you do manage to resurrect one, but i fear it is generally a waste of more money if you do anything more that a gentle blast of air from a distance.
and help save the Cod stocks too, £7.00 for fish chips n peas is killing me these days, but WD40 bumper cans are now only £1.99, cheaper than ever!