As a ground engineer working Hajj operations in northern Nigeria I can confirm that a common problem was passengers hand carrying small Chinese cooking stoves and about a litre of kerosene.They were not happy about leaving it behind and only the threat of being left behind themselves would induce them to give it up.
Not dangerous goods but many pilgrims from the northern city of Maiduguri carried buckets of honey to sell in Jeddah and in the usual rugby scrum the stuff ended up everywhere - I once counted 11 shoes stuck to the tarmac after A departure.
Everyone in aviation should try to do at least one Nigerian hajj operation - it is like nothing else and will leave you with enough stories to fill a book - some of which you wont believe yourself!