If the bottles have caps that are fastened with metal clasps, I’d avoid closing the caps, as the bottles will then be airtight. A microclimate could then form inside any bottle where damp is present, and this would be bad for the glass. It’s better to keep them open so that some air can circulate.

To protect the labels, you should store the bottles somewhere dry and without too much light. Paper is light-sensitive and can easily yellow and become fragile if it’s left in direct sunlight, for example. Sunlight will also cause the labels to detach more easily, as the glue used to attach the labels will deteriorate. Similarly, any lettering on the labels will fade. If the labels are coming loose, you can reattach them by applying a small amount of acid-free glue, e.g. from Lineco. You can buy this from suppliers of archival products.

Kind regards from Maren, objects conservator, and Alexandra, paper conservator