ive used it by sucking it in through a vacuum line

 

I've used berryman's b-12 and seafoam in the tank, crankcase and also as an TB/intake cleaner (ford contour) seemed to work well although i wasn't trying to get rid of a prob but just prevent more like you are doing.

 

Great product. You should buy 2 cans per car. Put 1 can through the gas tank. And, no....it will not smoke when done through the gas, but thats because it is only cleaning your fuel system, not the motor. Put 1/2 of a can into your "oil fill" tube, right before you change your oil. Put another 1/3 through your vacuum line.........and watch the smoke show. I put a washer in my throttle to keep it at around 2700rpm, while smoking. I have 56K on mine and it made a huge difference in idle quality, throttle response, and even performance. Granted, my car is tuned. I did it on my 2003 truck (32K), my 97 GT (56K), and my cousins 2001 Maxima (75K). All with excellent results. Its the only product that has ever truly worked for me.

 

Im sorry, I want my car to turn over when I try to start it the next morning. j/p