A steady hand, a cocktail stick with the pointy bit sliced off, a small glob of contact adhesive, the type that needs to cure for a few minutes to get really tacky. Evostick is a common brand.
Use the flat end of the cocktail stick to apply a really thin/small amount to the bead, don't wipe the stick afterwards as you will need both surfaces to be tacky. Make sure you leave the machine in the same orientation as when you applied the sticky stuff to the bead. After 10 minutes or so use the tacky end of the stick to make contact with the tacky spot you made on the bead. Pull gently and it should come out, if it doesn't then try again until it does.
Some people use to recommend superglue but this is just too runny if you use too much or have unsteady hands, as you have to hold it in place until it sets. Contact adhesive is far better for this job as it is a lot easier to apply and does not need you to hold it in place until it sets.
Hope that helps.
Jerry