Shredding is the ONLY way to 100% completely, destroy valuable and sensitive data stored on obsolete devices such as hard drives, tapes, magnetis media, memory as well as circuit boards. It is physical destruction with absolutely no chance of recovery, and by far, the safest form of destruction.
Degaussing hard drives (also known as demagnetizing or bulk erasing), removes data, formatting and control information from tapes, hard drives and diskettes. Although degaussing can remove data, it is not considered reliable because of human error, software unreliability, and they increasing ability to recover lost data.
The U. S. military has policies regarding the number of times degaussing is necessary depending on the level of information being destroyed, which only supports the unreliability of degaussing.
