okay here it is. Take a key and smoke the "neck" of the amp. Thats how I open my sustanon all the time. To be honest until a few days ago I never heard of an amp opener or ppl using files or pens or ovenmits. A butter knife will work too.
Here is my experience with Infar cyctaho's, they were a bitch to open. First cycle, first injection, my partner opened it with a towel around the neck everything goes fine for him, then my turn I cut my $#@? finger and blow the amp in my hand and the bleeding don't damn stop !
In my whole cycle I broke 4 amps wich fucking sucks, I highly recommend a amp opener, even though the pen trick is good if you have the proper technique.
I just used a pen top while wrapping the base with a towel, in case it shattered, which happened only once and snap the top towards you, and not your face, it comes off clean and quick.