I use a narrow-neck funnel to pour the “arsenic” (which is sea salt) into the bottle, and I clean any spills or drips off of the bottle top with a damp cloth.
E600 is my adhesive of choice when securing the cork or lid into the opening of each bottle top which protects the contents. Inking the cork, before gluing into place, helps me achieve the aged-look I desire.
This label is from the 7 Gypsies Apothecary Labels. I distressed them with Walnut Stain ink, and many were crumpled and ink added to the wrinkled ridges to give them additional aging. Clear contact paper was added over most labels to preserve them (leaving 1/8” around all edges to help with the seal).