been a long time since i cleaned a whitie but as for the perch and the wallies i clean them wheni get home i just leave them in the box of the truck until home, toss them in the sink for the amount of time it takes to get changed into some dry clothes and put away my gear and crack a brown bottle, usually about 25 minutes before i start to clean them. usually on a pizza box left over from the night before hahah they clean pretty easy the reason for the cardboard is that it soaks up a bit of the slime that comes with the thawing of them, but no different then in the summer other than the guts arn't so sloppy,
good luck on the hard stuff.