Admittedly, Senku was not actually expecting that.

"Ink and oil don't typically work the same so that could be your problem." He observed. "Or it could be a combination of both, you might still have to check the wiring to make sure it's not catching. Barring nothing else, the oil in the kitchen would work fine. Hydraulic fluid is typically 99% oil, but I'm not sure we have any additives."