@SDRocks I agree with sneezles and loopie. Just save your yeast and don't bother to try and wash it. I almost always save the yeast slurry from the bottom of the fermentor.
I sanitize a small mason jar ( in your case even the very smallest 4oz Mason container is enough).
I swirl the remaining bottom trub in the fermentor (after bottling or kegging) to get the yeast back into suspension.
I fill the mason jar completely, all the way to the very top. I don't want any headspace that might help CO2 build pressure.
I spray down and clean the now dirty rim and threads with star san and screw on the cap but not as tightly as I can. Any junk on the jar/lid threads will make a glue that you don't want.
I do all this pouring from the fermentor into the small jar with the small jar in a large mixing bowl to minimize the mess.
When it comes time to reuse, pull your yeast jar out of the fridge near the beginning of your brew session. Look at the lid, if it is bulging then the contents are under extreme pressure and it might not be worth opening (I learned this the hard way). If the lid is ok then open completely and smell your yeast. It should smell like the day you stored it. If you smell anything off then throw it away. If everything checks out, put the jar on a plate and lightly put the cap back on. The yeast will warm up for pitching and possibly bubble out. When it's time for pitching clean off the container with Starsan. I have gotten pretty confident in my process by now and just take out the yeast jar and submerge it, without opening, in a larger bowl of Starsan until I need it.