If it can corrode steel, then it probably wouldn't be able to kill the odor of decomposition, since it would destroy the body completely, eliminating the need to cover up the smell. Thermite is capable of burning through steel, although not necessarily corroding it. Nitric acid will corrode steel, but not to the extent I think you're thinking of. It can create small pits in it, but the more metal it corrodes the less acidic it becomes. A caustic solution (i.e., NaOH) may work at corroding steel, as indicated by <a href="http://sti.srs.gov/fulltext/ms9900055/ms9900055.pdf
">this article</a> from the Savannah River Site (a nuclear waste treatment plant not far from where I used to live).
The majority of TV shows blow chemistry way out of proportion. MacGyver had an episode where he used a bottle of water + sodium metal to blow a hole in a twelve inch think cinder block wall. CSI and NCIS get science wrong sometimes too. I love watching these shows just so I can be like "Hah.. that's SO not how you do GC/mass spec/NMR".