replacing joker valve the hard way

[Dave22q]

Like an idiot when the pump on my Raritan PH II resisted while flushing I simply pushed harder. Got most of the solids out of the bowl before she jammed fast. Siphoned out the contents of the bowl but suspect the pump housing is full of black water or worse. My readings seem to indicate joker valve blocking the outflow is the likely cause. My understanding is that the best I can do is unbolt the exhaust hose after putting something down to catch the liquid from the pump. Then, using gloves, pull out the old joker and insert the new. Anyone have a less messy idea or is this about the best I can do?