Yep, the dirt thing is the most important part of the procedure. My method for using ARO for short periods(if your using 30% Nitro its very corrosive, so if your not going to run the car for a few days ARO is a good idear) is to clean the engine fully around the carb, filter boot etc and then put about 10 drops down the carb, THEN re-install a clean filter(or the same one if its not too dirty) and then turn the motor over with the box or ps, this will get enough oil to the bearings and crank to keep them safe. If your going to store the engine for weeks or months I would add to the above procedure a few drops down the plug hole as the final touch(no need to then spin the engine), then re-install the plug and cover the exhaust outlet.
Best way to clean the engine around the plug is a pump spray bottle with Metho(DNA) in it, hold the car up-side down and squirt it up there, let it drip out a bit the give it a good hard blow with your lungs to dry off the metho YOu can do the same thing to clean the carb/airfilter area, just don`t let the metho run into your clutch bearings

TM