Don't switch it on or off near your record heads either or the collapsing magnetic field will polarize the magnetism in your heads and sound like kaka.
You should be at least 4-5 feet away when you turn it on, then slowly approach the heads with it while waving it back or forth. Kind of a hi-tek witch doctor thing. You can chant a mumble too if you want to remove evil spirits from your studio.
While you're doing this keep moving it closer and closer to the heads till you're right there (i.e. 1-2 inches) then still waving it back and forth move back to where you started. That will demagnetize the heads.
If you actually do the no-no I describe above, you'll need to get a more powerful degausser to correct the damage caused.