How to export a render as an item to add to a comp?

I made a fire animation, and I want to export it in such a way that I could add it as a tool in the node viewer (if possible). Whats the best way to export/save your comps to add into other comps?

If you just want to use it as-is, and you wish to have it in one node, you can simply group the nodes together. Select all the nodes and press CTRL-G. Then just copy the one group from one comp to another.

You can also just copy all the nodes over.

Ok, great thanks!