The extra knife is a part of a BP but it is not selectable at all. I’d like to remove it. Is there a way?
You actually have it selected in that very screenshot 
With it so selected, just press delete.
Or right click it and do the same:
This will of course cause errors in the BP if and where that mesh is referenced.
The knife selected is the one I want to keep in there. It is a static mesh. The extra knife with handle is not selectable and I cannot delete. It is a BP I made but it does not appear in the Game World so i’m not sure why it’s there.
In that case it must be a part of the skeletal mesh, in which case you would need to edit that. That seems strange as we are seemingly looking at Mixamo’s XBot, but there are no other meshes there.
Where did you get the (character) mesh from?
That mesh is from the Game Animation Sample Pack. I imported that character into my game to use to movement mechanics. I’ll have to take a look at the skeletal mesh. I might just restart the whole project as I didn’t get too far into it. Use what I learned to avoid that mistake.
if it is part of the skeletal mesh, there’s a hide bone node you could use to hide it.
Oh, yes it is… they shouldn’t have used those ■■■■ colours.
That is very odd then, as the character definitely does not have a knife in its mesh.
You did nothing at all else to the character BP? construction script is empty?
I might just restart the whole project as I didn’t get too far into it. Use what I learned to avoid that mistake.
While a clean project may be just the ticket, it seems it would be hard to avoid a similar mistake when you never figured out what that mistake was, I’d keep trying to figure this one out myself, for the learning experience 
Turns out that I just had to close and reopen the project. I went to try and figure out the skeletal mesh just now and extra knife is gone. Thanks for your help!