This topic has been covered many many times.
If you want to use alcohol make sure you have your hop up rubber off.
As for using silicon lube inside the barrel this seems to be a matter of personal preferance. I personally don't clean my barrel with ANYTHING but a clean swab cloth and pull it thru....make sure your hop up is turned all the way down or you risk damaging the rubber.
I am still shocked and wonder why people decide to put any silicon lube in their barrel. Doesnt really make any sense to me. For one, you risk swelling your hop rubber and two, the cleaner and drier and smoother the barrel the more accurate your shot is going to be.