You can sweep at Impel Down for the price of 20 belly, this feature is awesome since it can save us a lot of time.
By using the sweep, we will get to the first floor of our last completed level. E.G: if you have completed floor 40 from Infinite Hell, you will be able to sweep until the first floor of Infinite Hell. You will get all the rewards as if you played through it manually.
'You can use SWEEP feature at the start of any stage, i.e. Floor 1. '(You have to at least cleared last floor of Beast Hell stage)
Also with higher VIP levels you can reset Impel Down again so you can sweep and get all the rewards again. This is mainly useful in 2x events. It costs 200, then 300 belly to do extra Impel Down resets.
Pro Tip: Make sure you have reset your Impel Down Challenge the day before x2 drop event so you can save sweep for x2 drops!