Maybe I've been a bit agressive but you've posted this in Science - had you done so in Body and Soul I'd be a bit more gentle.
The thing is that Science likes to have a mechanism - a suggested reason why an observed event might occur. That doesn't mean that unexplicable phenomina do not eventually end up getting incorporated into conventional wisdom but it makes the stakes that much higher.
Extrordinary claims require extraordinary proof.
When the claims seem to contravene existing knowledge that proof has to be very extraordinary indeed!
The sharpness of a razor is due to it's thickness - in order for a magnet to sharpen it it would need to remove atoms from it, and in a selective way too! This breaks a number of well known and long standing physical laws.
As you so rightly say the proof of the pudding is in the eating.
Car manufacturers would sell their grannies to get one up on the competition, they perform exhaustive tests on technical enhancements - Does BMW use magnetic fuel devices? No? Mercedes? Rolls-Royce? Ferrari?
I don't know whether you are just an enthusiastic user of these products or are involved in seperating people from their cash for them. If it's the latter you need to be aware that trading standards are taking a legal interest in the claims that are being put forward for them here for example:
http://www.oft.gov.uk/News/Press+releases/2006 /47-06.htm