If whilst meditation I find that an idea or a memory plagues my thoughts, I find this technique helps.
I imagine I’m walking through a forest searching for a big pile beautiful leaf lying on the floor. I pick a leaf up and start writing down one thought in focus. I then mindfully place the leaf in the river. And watch it float away.
I find this helps if I am burdened with ten or twenty unrelated ideas. Circling from one to the next.