1. You guys are weirdos, it's much more fun having EVERY wrench from a different brand :) . And much harder.
2. Are you sure it wasn't 1-1/8, which is 28.6mm?
Use http://en.wikipedia.org/wiki/Phosphoric_acid
You shouldn't have problems with buying 20-30% solution. It also gives protective coating, not only removes rust.
There's also 5/32"==4mm and 5/64"==2mm when it comes to allen :) .
Over 1" you can grab nearest metric if you have every 1mm, it will fit for emergency work.