Cardboard is readily recyclable in any condition and in many places. So it pays to call around to local recyclers and haulers to get the best price if you are generating a lot of it.
Metals are also easily recyclable at numerous locations in King County.
It typically pays to have container service if you will be generating large quantities of a material and will need multiple hauls per week. If you are generating smaller quantities and have the staff who are interested, self-hauling is an option. A few subs or employees may be willing to take charge of your metals or cardboard at the end of each day for the value of the materials. Self hauling also increases the options for recycling since there are numerous drop off centers for both metals and cardboard and of course, you will be eliminating the container rental and hauling fees. Numerous metal and cardboard recyclers are located in the King County area.