Toyota Tacoma frame rust

Just bought a 2006 Tacoma last month. While changing the oil and a general review underside discovered a lot of rust on the frame, particularly at the rear connection is bad. (I know your supposed to check this before buying.) The mechanic thinks there might be a Toyota year recall on this problem however I cannot find any thing for this model. Does anyone have anything on this?

 

Pics? Can you wire-brush it off or has it already pitted?

 

The frame in general is rusted, however at the rear bumper connections the steel is in flakes. Toyota says there is no recall on the 2006 model for this, I need to look over and see if some of this can be replaced before something fails.