The MSDS was easy enough to Google. Nothing jumped out at me, looks fairly harmless.

I'd definitely keep it to relatively small concentrations to avoid viscosity issues and whatever emulsifier they happen to be is. You might also have it PH tested. Some emulsifiers are acids. Is the drum it's stored in coated on the inside with anything, or bare metal? If bare metal and this stuff has been in contact for years w/ out trouble, you're probably fine.