Yes, you can use it. I have a plastic bottle with an attachment that hooks up to the draft tower after the faucet has been removed. I purge the line of air while filling it with cleaning solution. Let the solution sit in the lines for a half hour and then empty the line of cleaning solution and flush with starsan/sanitizer solution.
As far as keg cleaning, I also have one of those long dip tube brushes that I use when I break down the keg for a more extensive cleaning.
Et Tu, Brew Day?