It is a good idea to pack scats into sealed containers, such as margarine, ice-cream or take-away containers to try and minimise smell and keep Australia Post happy.  It also stops the scats getting squashed, which can help if trying to determine what produced the scat.  Also, where practical (i.e. if scats are not too wet), it is best to collect scats into paper envelopes rather than plastic bags.  This cuts processing time significantly by enabling me to put them straight into the drying oven on arrival, instead of having to transfer them and the information from the plastic into and onto oven-proof receptacles (eg, paper bags) for drying.  The collector can write any information straight onto the paper envelope.  As well as saving time, the risks of handling undried scats (eg, hydatids) are reduced and the scats sweat less and start to dry out a bit, hence usually smell a bit less.  You can purchase suitable paper envelopes for scat collection from Prospectors Supplies (http://www.prospectors.com.au/p-1444-100-x-200mm-paper-soil-bags-geochem-100-bags.aspx or http://www.prospectors.com.au/p-1445-125-x-250mm-paper-soil-bags-geochem-100-bags.aspx.  Or if sample size is small and not too wet,  ordinary envelopes may be adequate.