While this thread is headed molasses, I'll add this for general info....
IMHO the first thing to do is to decide whether rust
conversion (to phosphate) or rust
removal is required.
If rust
conversion is required there is a product called
ranex rustbuster (from
bunnings type shops) which is available in a spray bottle, obviously a phosphoric acid type preparation which converts a lightly rusted finish to a dark grey phosphate - it depends on the film of rust to have something to convert to the phosphate
If rust
removal is desired, citric acid can be used instead of molasses. Mixed 2%-5% powder to water, it is great for removing the rust that is usually on garage or clearing sale items including screws, chisels, screwdrivers etc etc. Items need to be totally immersed in the mixture and it doesn't seem to "keep attacking" the base steel or iron. After 8hrs, the first layer of corrosion can be carded off with coarse cloth or hessian, and the item returned to the solution.
NB: Use only on ferrous alloys or iron (they're the only rusters anyway)
Citric acid is obtainable from grocery suppliers and is used in the food industry in things like lemonade (also has other industrial uses).
The stuff I use is produced by
Windsor Farm Foods - Home. I imagine that they would be happy to tell you who sells it near you. A 1 kg container of the powder is under $15 - lasts a long time