Q:
Wool Scraps and Low Level Mats
If you look at the loot you’re getting from running in areas where you’re down-leveled, you’ll notice that not all of it is lvl 80. Salvage the low level armor pieces you loot for their respective material (light = cloth, medium = leather, heavy = ore).
Also, be sure to open the loot bags you get, rather than selling them, as they are not upscaled based on your character level, and they’ll contain mats that are appropriate level for the zone.
Admittedly, the low level cloths and leathers are difficult to farm effectively, but I hope that helps.
The wiki has some useful information for that sort of thing(although it is far from complete).
For salvaging there is http://wiki.guildwars2.com/wiki/Salvage_Item
You can use the levels of the maps where the items drop to figure out the levels of gear that will also salvage into similar things. Except for the tier 1 items all other salvage items gives you materials from two different tiers.
The theory is that you get more of the items from the lower tier than the higher tier but that shouldn’t matter if you are doing this to level crafting since you will need both anyway.