Place the pens in a resealable bag, place them in a horizontal position and squeeze them to expel as much air as possible (or use a vacuum sealer) and zip them up. You can also try airtight containers for storing food or even airtight cigar tubes for your nicest pens. If you have lost the pen cap, store it in a resealable bag, with no air in the bag. It goes without saying that the cap of the fountain pens should be changed immediately after each use.
Double-ended pens, such as Tombow ABT double brush markers, will benefit significantly from being stored sideways to allow ink to flow to both ends. Storing pens this way prevents leaks and prevents pens from drying out, as the heaviest and slowest moving ink will be ready at the tip when you need it. If you don't intend to use a fountain pen again for a fortnight or more, it would also be wise to clean it before storing it; otherwise, you could experience problems of dryness when you pick it up to write again. This allows the ink to remain on the tip of the pen at all times and makes it come out more easily when you finally want to use that pen.
If your location is humid and you don't use air conditioning or a good dehumidifier, consider buying small packs of silica gel to store in your closet to protect the pens by absorbing moisture. Whether you have another pen that you use more often or you just don't write much, you might be wondering if you should use more pens. To safely store hard rubber pens or colored celluloid pens that are prone to fading in the long term, consider removing the bags from them. Fountain pens are best stored horizontally to prevent leakage, whether in a pen case, presentation case, shelf or drawer.
This material can quickly spread everywhere when pens are handled and blocks air transfer, accelerating the decay of celluloid or other cellulosic pens. Storing pens properly can prevent a variety of problems, such as pens drying out or getting stained and unwanted ink marks on the fabric. Airtightness will retain the acids released by all celluloid and cellulose acetate pens, and these acids will accumulate in the atmosphere inside the airtight cabinet and accelerate the decomposition of the pens. Light, especially sunlight (which has a high UV content), can degrade the surfaces of both hard rubber pens and pens made of celluloid or other cellulosic resins, such as cellulose acetate or Forticel (which Sheaffer called Radite II).
This may seem obvious, but many people forget to put the cap back on their pens or don't put it on at all, and this greatly contributes to the pens drying out. Use them only on disposable pens and don't assume that, since a certain ink is safe in pen A, it is automatically safe in pens B, C and D. Except for pens with piston joints or cork joints, store them empty, clean and let them dry. The pens contain viscous oil-based ink and, therefore, the pens must be stored vertically with the tip pointing down.
A pen can works well for this purpose; they are available in all shapes and sizes to fit the desk and decor.