I'm thinking something similar to this floor squeegee, probably with wheels on the far edges and maybe one in the middle to quickly corral the fuel:
Floor Squeegee
Get the fuel pushed away from the bots quickly so removal can happen safely.
I'm also thinking of making a couple of exactly sized boxes to dump fuel into that measures out 50 of them for easy *counting* to put back in the hopper containers. Just fill the box and dump it in. Trying to come up with ways to make my field reset crew jobs a little easier and the new CNC Router that will be mounted in the garage this weekend will need something to work on.