dont even need to brush it in pal.
brick needs to be dry, i just poor alittle into the cap and drip onto the centre of the stain, allow it to spread out and soak in, leave 10,mins or so (only put enough on to just cover the stain, you dont want to spread it). then just rinse away and add more pressure if needed.
if you need to repeat it you can work it in alittle but again it needs to be dry to start with (90% first treatment is enough).
one tin (5ltr?) will do you for years, unless your working down at castrol!