If you put your needle directly into the old cotton, you most likely WILL get cotton fever.
I do this sometimes, but I always have fear of cotton fever in the back of my mind as I'm doing it.
Im not sure that I agree with this completely. I was an IV heroin user for quite a long time and injected it tens of thousands of times, and each and every injection i did, I saved the cotton and even left it nice and wet/juicy so that i will have some nice cottons for a cotton shot later on. So you can do the math and figure out how many cotton shots I have done in my day. I would do my heroin during the day/early evening, and then at night when it started to wear off, I would do my cotton shot using all the cottons I had used throughout the day(around 4-6). My method was different than yours but I can guarantee you I got almost every last bit of opiate alkaloids out of those cottons that was possible.
Also, we dont have needle exchanges in my state so I would basically use a needle until it broke(around 30 times), and I didnt usually have access to sterile supplies.....I was a straight up junky, I just needed my fix and to hell with the consequences. So, needless to say, I was constantly taking risks of getting infections, etc....allthough I will admit that I am very good at injecting and always have been. It is an extremely rare occurence for me to miss a shot, so I was at less of a risk of getting an abscess,
Anyway, my point is, when I did my cotton shots(every night for several years), I would basically just thrown all the cottons in a spoon, add about a needle and a half worth of water, and then heat it, then squish it with the needle cap, then heat it, then squish, then heat, etc...about 3-4 times. This usually made the water very dark and it also reduced the amount of the solution down to a size that could fit into one needle because of all the heating.
So after I did all that I would pick all the cottons up with my fingers(they were usually burning hot cuz I was usually to impatient to wait to inject) and then squeeze all the juice out of them until the cottons were almost bone dry.
I would then take a new little cotton piece and put it in there and suck the solution up through my syringe and then inject. It would usually get me atleast a nice little buzz.
Anyway, I NEVER got any infections or diseases or cotton fever.....EVER. And I did it tens of thousands of times. So when you say that you will get cotton fever about 5% of the time if you always filter through a new cotton and that you almost definitely will get cotton fever if you filter through the dirty cottons, I have a hard time just sitting here and not saying anything. because that either makes me an UNIMAGINABLY lucky man, or your fgures are off.
Im not trying to say that shooting cotton shots are safe, or that my method is safer than anyone elses, but I am saying that you seem to be making the risks of doing a cotton shot out to be a bit more dangerous than they really are. No offense, its just I have also known many people who injected just like me and did there cotton shots just like me for very long periods of time, and sometimes in even more dangerous ways, and none of them have gotten cotton fever either, or any other complications.
But please, anyone who reads this, dont think that im saying that this is safe...it is most definitely not, I just wanted to be completely honest about what risk you are taking if you do choose to do a cotton shot.