Mini Sparge in Strainer -- Fail

So in trying to get rid of the last of my stock of extract, I am brewing several batches that have a TON of specialty grains that I mash in a pot without putting them in a grain bag because there is just way to much. To sparge, I usually put them in a strainer and use the sprayer from the kitchen sink to spray hot water over them. It usually works really well, but I just tried to make a Chocolate Granola Bar Stout. I used half a pound each of flaked barley and flaked oats. This caused some serious issue with the sparge method, and I may have aerated the wort and there was still a lot of residual grain in the wort at boiling.

I have a Java Stout that I was going to do, and it uses a lot of flaked grains as well, and I foresee this problem happening again. Is there a better way to sparge 8-ish pounds of specialty grains?

Switch to AG and save all your malt. Oats need to be mashed (and cooked if they're whole oats). They're probably gumming up because you're not using them right.

I have switched to all grain, but I have some extract laying around from the summer before I switched. Just trying to get rid of that...

When I was doing spaghetti-pot partial mashes and I had a ton of grain, I would often pour everything out through a strainer into my grew pot and then dump the grains back into my mash pot. Then add my sparge water, stir it up and repeat the process.

If I didn't do that, I did basically what you did except I ladled my sparge water over the grains in the strainer.