Here’s my top tip for easy, quick mess-free unpicking.
No pile of tiny cut threads to deal with, this is my favourite way to unpick machined straight stitch. If you’re machine tacking make sure you leave long thread ends at the start and end of your machining to make the process even quicker and easier. I always machine tack knitted fabric neckbands this way so that I can quickly take them off if I need to adjust the length of the band to get it lying completely flat.
The only situations that I wouldn’t recommend this method for is on very lightweight delicate fabrics.