I worry about heat dissipation, but maybe that's considered.
When I printed my "underground newspaper" on a dot matrix printer, back in high school, I thought I'd get away with so much printing without my dad knowing by putting a cardboard box over the printer to deaden the sound. It worked until it didn't. Luckily the printer had a thermistor on the printhead and just stopped versus continuing to brainlessly grind until seizing-up.
We had a largish cooler for fishing. I ended up putting a towel in the bottom of the cooler to absorb vibrations, closed the lid over the power cord. I checked the temperature a bunch at first to check for overheating, but it wasn't an issue.
We didn't keep at it long, but that kept the noise from being an issue. It was a slow, messy process and we were too busy to pay attention to it over long periods of time.
