Is it possible to strengthen or weaken embedded magnets by exposing (or rubbing?)with other stronger - say rare earth - magnets?

I heard somewhere that heat can weaken a magnet.

Actually, any intense temperature change can affect the strength of a magnet. But I don't know anything about the effect another magnet will have.

Also, a sharp smack on a hard surface will weaken magnets.
It could even completely ruin the magnetic pull, so be careful. This is not the best method to weaken a magnet, although in theory it should work.

-Vinny

Rare earth magnets are sensitive to extreme heat.

Some magnets are magnetized after they're formed by subjecting them to a strong magnetic field, so technically it's possible. It's not something I'd try at home though. You'd probably need some pretty detailed info on the properties of the magnet you're working on, and I don't think many people would have the equipment available to create a strong enough magnetic field to do the work.

While smacking a magnet will weaken it smacking a piece of iron repeatedly will magnetize it. You are rearranging the +'s and -'s into line, or out in the first case. Had a tiff with 5th grade teacher about this. She was amazed when I proved it. The question was "How to make a magnet?" and she marked my answer as wrong on a test. I had read ahead in the book. That day we all learned a little about science and teaching.

And I think the heat required would be like using a blow torch on it - I don't think you could get to the needed heat with anything else. In essence you have to make the magnet hot enough for the atoms to re-align. I think it would be difficult to do so and get the right level of reduced magnatism.

I think it would be easy to overshoot if that makes sense.

That might work on an iron magnet, but not a rare earth mag. Temperatures over as little as 170 degrees will destroy them.