How do I make a cartoony drawing look old?

If you saw my drawing of Tom gagged with a bomb you should know what I'm talking about.

This is done with Paint.NET. This method is a bit different from the one I used for the drawing of Tom but it's close enough. I hope
Okay, I'll try to explain.
1. Choose a picture you'd like to make look old and open it in Paint.NET
2. Click "Effects", then "Noise". Decrease intensity and color saturation, change coverage if you want. Press "OK"
3. Effects > Photo > Soften Portrait. Decrease softness, change lighting and warmth if you want. OK
4. Effects > Blurs > Gaussian blur. Decrease it. OK
5. Not necessary. Create a new layer above the layer with the picture. Double-click on the layer in the list of layers and change it's mode to "Multiply". Choose black as primary color and white as secondary color. Choose radial gradient and add it by holding and releasing the right mouse button. If you don't like the result you can adjust the layer's trasnparency or, while you're working at this layer, go to Adjustements > Brightness / Contrast and change those settings.
6. Remember those light scratches and dots? Make a new layer and draw them with the brush tool, but make Transparency - Alpha low before that.

Well, something like that.