All you’ve to do is load the film into a canister with the wrong side facing up. This means that the wrong side will get exposed instead. The result … weird and funky colored photos like this … 
Here are some simple steps which I learned from some guys online …
What you need are two rolls of films. You are going to empty (waste) one of them, so it’s best if you have some expired or unwanted film to sacrifice. Let’s name the two rolls A and B. Roll A will be the roll which the film you are going to use, and roll B will be the ’empty’ one to load the film from roll A into. Confused yet?
To start, pull out all the film (!) from roll B and cutting it at the end, leaving about 1 to 1.5 inches of the film still attached to the canister. Remember … should you drink too much Red Bull and yank the entire film strip out … you’ll have to sacrifice another roll for this.
Next, take roll A and cut off the leader. Simple? 
Now it’s time to bring them together … take up the ends of the film from the two rolls together. Remember : the two opposite sides of the film should be facing up.
Now for the final part … use a black bag or do it in a total dark room … roll the entire content of roll A into the ’empty’ roll B. You can use a scissors to do this.
Once you are at the end of the roll, remember to cut the film leaving about an inch on roll A. You will need the roll A as the empty roll B next time. Hmm … do I sound confusing? Sorry but I’ve already tried my best 😛 You can now load roll B into your camera. You can cut off some of the leading end to make a new leader so that loading is possible. Oh, don’t forget to overexpose by 1 stop (eg. using ISO 400 redscale film, set your camera to ISO 200)
… my secret weapon!
I found this unused plastic pinhole camera which I’ve never bothered to use. I cut off the film pickup on the right, and used this to wind/roll my redscale film. Easy ain’t it? No black bag … no dark rooms 😛
