Re: disposal of the residue.
I have dealt wit this a few times for several materials that are not suitable for the liquid waste stream.
Contain the material and water in a tray that can be removed and left out for the water to evaporate. The tray may need to be made to hold the part. Place a disposable towel (I use lintless blue shop wipes for this) on the surface. It will sink as the water evaporates. When it gets down to moist muck in the bottom, wipe the muck out and dispose of appropriately. If the container needs further cleaning, rewet and a fresh wipe to repeat the process.
If it is possible to put a towel in the bottom before the work, it is easier, since the waste will be trapped between the two layers. I have done this with success when using a water tray below to catch runoff while drilling glass.