The best testing is our experience. We have been using our products on our own pens. And a lot of these pens are “Rare Pens” or uncommon and interesting pens that we would not risk damaging.

Sac Testing

Sacs were tested with both Not Just Deoxidizer as well as Pen Flush.

Some were filled and emptied but left wet with product. Some were rinsed after emptying.

They were left to sit for six months to observe for any degradation of the sac.

Cap and Barrel Testing

Celluloid, acrylic, and hard rubber caps and barrels were tested.

Parts were soaked in either Not Just Deoxidizer or Pen Flush.

Some were rinsed, and some were simply left wet with the cleaning solution.

Pen parts were observed for six months for any signs of cosmetic or structural changes.


Sacs: No visible damage, no change in elasticity

Caps: No visible cosmetic changes

Barrels: No visible cosmetic changes