that is certainly a good sign of illness if it happens before the week is up. but in my experience it can take quite some time for those symptoms to show up in a sick rat. tween has been sneezing and breathing slightly harder then normal for 3 days but she is still just as active and no red snot or goobers (can't spell the right name for it tonight it would seem). in the past the red stuff has taken a few days to a few weeks to show up from the time i suspected an illness. so if you do see those signs then a vet visit is definately needed but you may only have sneezes and slightly raspy breathing for days to weeks prior to those signs. if your rat is new then it very well can and probably is the new home sneezes. but if after a week or if they start showing any other signs of illness then a vet visit is due.
as for dusting the cabinent if you use a damp cloth and rub slowly the dust will not escape into the air but will be trapped in the cloth (the things you learn when you live with an asthmatic and progressively ill grnadmother! :grin

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in reference to the YN: YN is different then just paper. it is very tightly rolled pellets of paper with no toxic inks. i believe it is in the rolling that the most odor control benifits originate. i know with merely shredded paper the odor can become quite nasty in only a day or so. also though the pellets get wet they do not feel wet and absorb the moisture quickly so the rats do not get wet (its like the huggies of the rat litters that way). then too though the pellets will get larger and more fragile when wet they do not break up into dust.
as to where you find YN and price, where i'm from in Canada a 30lbs bag can be bought for $15 in most pet or feed stores. i have even found it in walmart and sobeys (a grocery store) though the price is a bit higher. if you look around a bit you should be able to find it fairly easy. it is marketed as a cat litter.