http://www.tip.it/runescape/summoning_table.php?search_type=pouch

 

what is the 'shard trade-in value' and 'scroll trade-in' and 'trade-in level'?

You can trade pouches and scrolls for shards at the orge enclave summoning chappy.

Its 70% of the shards per pouch and roughly 50% per 10 scrolls.

The trade in level is required the level you need to trade in the scrolls/pouches.

 

The value is the shards *25

is it common practice to do this? if so... how so? what pouches are good to do this with

It's very common place.

 

Any pouch that makes a lose via selling or of no use to you should be traded in when training summoning to get back shards to lower costs.

 

If a pouch takes 100 shards thats 2500 to buy them.

But trade it in and you get 75 back

So you have 175 for the price of 100

 

And you can trade in again and again and again so if you worked it out fully buying 100 shards could equate to like 300 - 400 shards worth of use