You can wash that yeast, very easy to do.
You are actually on step 1 now.
Just pour off most of that beer leaving the yeast and trub and then follow the rest of the video.
Correction: you were already trying to wash it. With what you have there, just pour off the beer, add boiled and cooled wash water to fill it back up, and then wait 20 minutes for the trub to settle out. Then pour the yeast into clean containers.
The containers that you pour into don't necessarily need to be clear, but that would be nice.
You could just put all that in the fridge and wait until you get some clear containers.