At end of the day there is nothing you can use unless very diluted. The EA moaned about the use of heat on that water mill job - but were happy about percarb when they researched it. The EA never found out about the hire company driver who drove the cherry picker over the bridge, it collapsed and the machine spilt oil everywhere. The hire company had to send a 20 tonne 360 to retrieve the cherry picker and then repair the bridge. Heat usually gets most things off