It can be done, sometimes, but it often depends on the colour and the shape of the object. And even then it's usually difficult and time-consuming. The trick is that because the Stuff>Everything Else items are usually on very high layers, there's plenty of room to play around underneath them to "cut" items into the right shape by partially covering them with pieces that are the same colour as the background.
It took ages to position right, but I used a tail (I think) to cover the gap in the pipe here
, and there's a slightly less-successful attempt to hide the gap in the skateboard here
(which took far more time than it was worth