For what they cost (with some very notable exceptions) it's better to replace the unit if it is at all dicky.
Ebay cheapo units tend to be a waste of money in my experience.
Using the correct filter also helps prolong the MAF life.
I still have one here where the wires on the sensing diodes are eaten away with corrosion, no amount of cleaning is going to affect that.
As mine is a D2, I don't have much direct feedback on the earlier MAF's, but I do know that one of the D1 units is eye-wateringly expensive.
Peter