Brush it off and continue to work
Leave it there until you are able to wash it off
Wash it off immediately with water and Neutralite
All of the Above
Don't worry about it because it is the subs responsibility to set up the equipment properly.
Tell the sub that you are more than willing to move that pallet out of the way, so he will be able to extend the outrigger all the way.
If there isn't enough room than it will be fine this one time.
The sub says, "I've has been doing this for years and there has never been any problems". You should probably let him do his job.