I think we might have 2 issues here. Some members report cleaning residue from the sensors. The 4 sensors I tried to revive were sparkling clean. So maybe if you have bad filter K&N (?) or holes in the system and sucking the dirt -MAF cleaner might help. In my case something cooked inside MAFs and cleaners did absolutely noting.
How do you get a good enough look at the film to determine that it is sparkling clean?
Standard filter in my case, replaced at regular intervals and no leaks.
One more experience, I drove my E320 for about 20,000 miles since I bought it before MAF triggered CEL. I replaced MAF and spark plugs at the same time. My mileage went up 20%. Don't think the plugs at 90k made the big difference, so my guess is, that before MAF went totally bad, it was giving incorrect signals costing me a fortune in unnecessary fuel burn.
Wonder if those, that succeeded with cleaning record their mileage?
If your mixture is off, high gas consumption could result. But the CE light warns you when the mixture is off (computer can no longer adapt to out of range MAF signal). So unless you drive with CE light on, gas consumption should not be seriously affected because no CE light means the MAF is within range.
Changing plugs (all 12 of them!) at about 100k km, made some difference to our car's fuel consumption - we check it regularly because it is mostly used for LD driving.
I just wish MB had used a more reliable MAF. I came across a technical paper once that Bosch presented at a conference. It was about research they had done to try and stop particles from depositing on the MAF hot film. So, it seems they are aware of the cause of the problem.