Cast Iron can break very easily if not packed properly or handled properly.
I witnessed a dropped cast lid hitting the side of the oven and cracking it right through the centre.
I've also seen plenty of lids broken just dropping on the ground. The cheaper chinese crap ones more so, as I imported them by the thousands for 15 years selling on to camping stores across Australia.
The best to look out for are old Metters brand or old Furphy made in Australia tough as nails pick them at swap meets on most weekends everywhere, 9qt ones 2nd hand will still cost $50 to $70 and worth every penny. New Furphy's are made in China now at a premium price.
To season heat up & melt wax first (unless realy cheap chinese...no wax), wash thorougly in hot soapy water, dry by heat, then add oil bringing to boil.
Never wash totaly out with soaps/detergent, scrape all burnt food out thoroughly and wipe with oily paper towel when cool of course especially for long term storage.
The idea of seasoning is to saturate pours of the cast with oil to stop rusting., so never clean out with harsh detergents and if you do, heat dry, then wipe or spray oil before putting away.
BTW COI owned by Primus Australia now.
Happy cooking.

