We are still seeing potential shippers and consignees trying to ship extra goods in containers without declaring them. Most of the time these goods are either personal effects or gifts being sent without any commercial transaction being involved. Simply there is space left in the shipping container and it seems an obvious option to use it up.

You CANNOT do this without declaring the items on the packing list/shipping manifest. Even if they are you own goods they still MUST be declared. If you container is inspected by the local importing customs officials they will be a best unhappy and worst seize the goods (or even the entire container). This applies to virtually all countries.

The goods can be just given a nominal value on any shipping invoice if they are gifts or in the case of personal effects all items must be fully listed. Note you cannot declare a 5000USD item as a 10USD gift. Most customs have systems in place to notice undervalued items and will issue there own valuation and also a fine.

In summary again everything must be declared. If unsure you should speak to you importing customs broker or freight forwarder BEFORE the container is shipped