Anything paramagnetic (i.e. iron-based material (incl. steel)), can be magnetised to an extent.
Steel magnetises quite well, such that "degaussing coils" were used on navy ships in the war to reduce the risk of them setting off magnetic mines (and built into some warships). To do an entire ship, however, requires huge currents, and thus huge coils and equipment.
Cathode ray tube monitors and some TVs had degaussing coils built in as well, since the shadow mask in the tube (so that the electrons only hit the right places on the tube) could become magnetised, which would bend the electron beam to hit in the wrong place. Early colour TVs (circa 1967 in the UK) were so sensitive to this, the shops would "install" them where the householder wanted, degauss the tube thoroughly, and then redo the receiver's convergence settings (itself somewhat non-trivial), leaving strict instructions that the TV was not to be moved around in the slightest.
Regarding magnetized tools, the trick is to apply an alternating field, and then slowly reduce that to zero. You can either reduce the current in the coil, or simply take the once-magnetized item away from the coil slowly, say over a distance of six to ten feet, then turn the coil off. Turning any sort of demagnetizer off when the tool is in its field may leave you worse off than before.
So taking the above into account, do you have a 240V to 110V 'yellow' site transformer? You might park your pincers on that for a while, then move it slowly some distance away. The transformers in those boxes are made cheaply and potted in resin (so you can't tell, he said cynically). They leak a strong field (well, most do), which might serve this purpose. If the tool wants to 'buzz' when you put it down on top or next to the box, you're in luck...
Much depends on how strongly it's become magnetized. If it's "a lot" you'll need a strong field to demagnetize it. The demagnetizing units for tape heads are usually very low power, they 'focus' the magnetic flux through an iron bar down the middle of the coil (which is in the body of the thing), but they'll probably struggle to do anything as big as pincers or pliers. Where I used to work, however, we had a bulk eraser for 13" reels of 2" wide videotape. It was a bit larger than my planer-thicknesser, and known as the 'fish fryer' - HUGE coil inside and the tape reel was rotated in the field, while it was slowly reduced to zero. Nothing came out alive...
If you can get access to an AC low voltage power supply, say from a school lab (nb. If it only does DC it's no use), you can safely connect that to a home made coil and pass the tool through that, but do NOT try this with mains voltages - at best you'll blow the breaker in the consumer unit, at worst it could be a fatal mistake.
I once made a fool of myself and got into serious hot water with the Domestic Controller, trying to take pictures of our TV. I thought it would be sensible to get a light meter reading first, so without thinking I held my Sekonic right up to the screen (BIG magnet round the moving coil meter part of it), creating a really infuriating purple patch. Big tellys (this was a Sony 27" - huge for its time) had a degaussing coil built in that fires up when the TV is turned on... but they're not very powerful. It took weeks for it to settle back down again.
