'Boxing' your worries
Here’s another technique you can use in your imagination. Imagine your thoughts as an object, something you can pick up and move. It’s best to imagine this object(s) in as much detail as you can. Perhaps you could imagine your thoughts as a certain shape, with a certain colour. Imagine yourself pulling out the troubling thought from your mind, and placing it into an imaginary box.
You might want to imagine a cardboard box, or perhaps you would want to imagine something stronger. If the thought needs locking away, perhaps you could imagine a safe, or some sort of locked box where you can put the thought away under lock and key. When the thought is safely boxed away you might want to imagine moving the box somewhere, so it’s no longer in your mind.