I had today exactly the same problem!
I let one of my four fresh hatched crested babies not long enough in the shedding box I explained above ...
today I took him out of the cage and found that he didn't she half of the body :shock: !
I filled up a plate for soup (not a bowl!) with a bit warm water and lied him into and didn't let him out for a few seconds. After a short time all the old skin were hanging loosy around him while he was walking in the water and I could pulling softy and all came off, piece for piece ...
It was easier than I thought ...
As well good luck with your babies and their future shedding ...
Greets
Peter