Feeding in a separate feeding tub is old school and has been proven counter productive over time.
A) associating food with the enclosure being opened has been proven to be false. I have never been bitten or even struck at within the enclosure. All my bites and strikes have come OUTSIDE the enclosure.
B) Nobody cleans their food in the wild. Plain and simple. They digest whole prey. A little dirt won't hurt them.
If you're worried about impaction, you can lay a paper plate or something similar down, but they often just take the prey wherever they want anyway.
Unless you've got huge chunks of bark or wood shavings, impaction shouldn't even be a concern. None of my snakes have EVER had an issue with impaction.
C) spot cleaning should be a regular practice anyhow.
If you're feeding F/T prey and they're making a bloody mess it's probably because you're heating too fast and too hot.
-You're more likely to get tagged moving a snake from a feeding tub while still in feed mode.
-Moving a snake that has recently eaten can also lead to regurgitation of the prey item.
-Moving the snake prior to feeding can stress the animal and lead to refusals.
The vast majority of experienced keepers feed within the enclosure.
All that being said, you do what works for you and your snake. There's no one "right way". But, I see seperate feeding tubs as a colossal waste of time and effort while adding extra stress to the snake. And for me, the snake's best interest is what comes first.