>>8401445I am an adamant believer in Pledge. Use a toothpick as an applicator. It'll flow into joints or around ball joints. Move everything around and let it sit for a few hours. Check the joints, if they're still not tight enough do another application.
I do not ever recommend using super glue as someone else suggested. The Pledge can be washed off, and even if it solidifies in a joint it will crack apart long before the plastic. I have found it will break down over time, but I consider this a good reason to revisit all my Transformers occasionally.