i found a way to make mop paint... well, not "make"...
but heres what you do, when a spray paint can is ALMOST empty, turn it upside down, then make a hole, yeah a hole, let it sit for some hours or a day (i would say a day is better)... why let it sit for a day you ask? so that all the pressure in the can leaves the spraypaint can... then when you´ve waited a day or so, just pour that paint into a mop or something, and tada!! you´ve got a really nice fast drying paint for your mop!