On Fri, 22 Feb 2013 23:05:54 +0000, Danny D. wrote:

The Permatex version of naval jelly MSDS says:
http://ecx.images-amazon.com/images/I/61w2z5V6VMS.pdf
10 Columbus Blvd., Hartford, Connecticut 06106, 877-376-2839
Permatex Naval Jelly Rust Dissolver is an acid based
thixotropic liquid for dissolving rust on iron and steel surfaces.

Had to look up 'thixotropic'.

http://en.wikipedia.org/wiki/Thixotropy

Certain gels or fluids that are thick (viscous) under normal
conditions flow (become thin, less viscous) over time when shaken,
agitated, or otherwise stressed. They then take a fixed time to
return to a more viscous state.