I would just soak them in some hot water, and rinse them really well before putting them in the cage/on the play area. 
I agree.yummy fresh baked cookies I am getting hungry
When collecting pinecones look for pinecones that are dry and clean. Stay away from the damp moldy ones, try to pick them as soon as they fall off the tree.
Heat oven to 225F. Place pine cones in the oven for 20 minutes. Then turn off the oven, but leave the pine cones in the oven for 2 hours to dry out. Pine cones will scorch and possibly start a fire if the oven is any higher than 225F.
Just wanted to add baking them helps open them and gets rid of the pine tar I also forgot to add wash them in hot water before you bake them
I know I forget to add washing them first I put it at the bottom but I don't think it came out right...lolI agree.you can also soak them before to prevent starting a fire..lol