How can I safely use a blender with hot liquids? One instruction in a new barbecue sauce recipe I'm trying out is to take the pot of simmering sauce and run it through a blender or food processor. 

I have now learned the hard way that blending hot liquid will cause the lid of the blender to explode off... there is barbecue sauce coating my kitchen, and I have some new burns to treat. 

So, what is the proper way to do this? Is there a safe way to use a regular blender like mine, or would I need a different kind of blender?
It can be a bit tricky, a couple of tips:


Use a lot less liquid in the blender than normal. Do batches if needed.
Vent the lid so the steam can escape. A lot of lids have a center piece that can come out. Using less liquid will stop stuff coming out the top. 
As Ocaasi suggests, you can cover the open lid with a kitchen towel as you start to insure there's no spray. 
Start the blender slow and then speed it up. This may not work depending on how fast your slowest setting is. But once the vortex gets going, the liquid won't splash. It's only when the blades start that you have that issue. Slower start speed means less splash (a vita-mix can start very slowly and have no splash at all, great for hot liquids but the price tag is a bit high).