Oh heck no, I put it right in there, along with the spice packet if it's a commercial one.

That's how I always make my corned beef too, in the slow cooker.

Annie

I don't know that lightly rinsing it would make it "bland", because it's been soaking in that stuff for a long time. But you may be using too much water if you've got a really large slow cooker, that can leach some of the flavor out.

I don't rinse it myself, just dump the whole thing in there. I add extra spices too, because the packet is pretty skimpy.

Another way to intensify the flavor is to remove the corned beef from the liquid when it's almost done and finish it in the oven.

Rachellen, I've finished in the oven too, with a liberal brushing of grainy mustard...

Annie

I always rinse that weird gooey stuff off first. Then I put the brisket in my slow cooker, pour in a stout beer, a splash of whiskey, the seasoning packet, some Worchestire and let it be until I get home from work. Always yummy.

Kate

I do mine in the
dutch oven and rinse the slime off....and it's never bland.
I find corned beef very very salty...I usually add potatoed, onions and carrots.....and scoop some of the broth out and cook some cabbage in it.
The potatoes and veggies mare always well salted. and taste like the spices in the corning liquid.
Linda C

I don't rinse it. Pop in in the dutch oven with the seasoning packet, an onion, fresh garlic, extra pickling spice and a can of beer and simmer all day. Pop in the oven for a few minutes before serving. Love corned beef and cabbage. DH likes the corned beef hash the next day better than the original meal. LOL

I've rinsed and not rinshed. The main difference I see is that when I rinse it, I get less foam.
I'm another who always adds additional seasoning.

Nancy