Power shear blades are magnetized and I need to demagnetize them. Can anyone tell me how to do this.?

To demagnetize metal, you must expose it to a magnetic field that fluctuates back and forth and gradually diminishes to zero. This is the only way to do it, so I'm afraid you'll have to buy or borrow a demagnetizer.

If you just need it noticably differant, just hit it with a hard object.

Take a hammer and hit the blades, see if a paper clip still sticks to it.... then try it again hitting it in a differant place... keep doing that till the magnetic field is minimal. (it is also a good method to magintize a screw driver or any thing like that)

hold them on a running electric motor ( ac ) like the one in a large fan, then with the motor still runing walk slowley back from it. that will degauss them. Look up degauss.

There is a temperature you can heat them to that will demagnitize them. I do not know the temperature, unfortunately. Try typing demagnitizing in your search engine. Good luck.