Solvent-based paint is a flammable liquid. So are contact adhesive, white spirit and thinners. Drain cleaner is corrosive, weedkiller can be toxic. None of it is unshippable — but all of it is regulated, and a half-used tin in a household move is one of the fastest ways to stop a consignment.
This group catches trade customers and households alike. A decorator sending materials to a job overseas, a manufacturer shipping samples, or a family packing the contents of a garage — all run into the same rules.
For a household move, our advice is nearly always the same: the garage and the utility cupboard are where shipments go wrong. Paint, thinners, weedkiller, barbecue lighter fluid, camping gas, aerosols and pool chemicals should all stay behind. They are cheap to replace, and every one of them is capable of stopping a container or a consignment.