I've had mixed luck with speaker magnets. More than once swept with a magnet only to find the spring on my hands and knees with the big flashlight right where the magnet swept.

Now as to carpets dissolving springs, there is a way to get solid springs again. And it involves rapidly rotating magnetic fields and atmospheric disturbances - a vacuum cleaner. The spring will materialize and will be one of those clinks you hear. Now if you start with a new bag...

The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh

Which explains a lot.