Good substitutes for WD-40 in emergency situation? I broke my bike in a poor location where I can only find poor rusted bikes. I am switching to one bike with rusted screws, I am trying to get things such as touring back rack and water-bottle holders to the new bike. I cannot find WD-40 here to take the screw out. The comment here speculates Kerosene and Naptha as the ingredients of WD-40. 


So how can I substitute the WD-40?
How can I find some physical way to remove the rusted screws in the bike?


Edit: I have solved the problem with time and Coca Cola in one screw. I let the screw to be 2 hours in Coca Cola and I got it off later. I am still unsure whether this is the best solution, at least it tastes good and it is easily available. More this kind of solutions?

I have a multitool with a file, saw and knives.
Actually, WD40 is a poor penetrating oil -- Liquid Wrench, et al, are better.  But the Coke trick works, supposedly because of the phosphoric acid.  Another one is to heat the part -- eg, get a piece of iron hot in a fire and then hold it against the fastener for a minute or two.  Works best if you can actually heat the female part of the connection, but tends to work even if you must heat the male screw.  Sometimes heating and then dousing with water will break a part free, if heating alone doesn't do it.

Of course, be careful of any plastic parts, and avoid overheating bearings.