The beaver pouch(u) was introduced as part of a Summoning skill rework on 3 December 2013. Players could craft unfinished summoning pouches anywhere in the world, and then infuse them at a Summoning obelisk to become usable. This update was not well received, and the change was reverted 2 weeks later.
It was made by combining a green charm with 72 spirit shards and Willow logs. This required 33 Summoning and gave no experience. The unfinished pouch could then be infused at a summoning obelisk to make the Beaver pouch, giving 57.6 Summoning experience.
Spirit gems, which are dropped by all monsters that drop a single charm and could be received from the Squeal of Fortune, functioned similarly to Runecrafting pouches and stored uncharged summoning pouches before an update. They now give a chance of saving a charm when making familiar pouches. Uncharged pouches did not have to be withdrawn from the gem to be imbued, although there was a glitch that made them not give XP while they were stored in the gem before the update was reverted.
Any leftover uncharged pouches may still be converted in experience. Clicking one in your inventory prompts a warning message saying: "this item no longer has use. Convert it and claim the xp contained within?". Choosing 'Yes' will convert all pouches in your inventory into 57.6 summoning experience each.