A couple of products you NEED to have in your toolbox are Power Gel and Pro Solve Gel
Some soiling conditions are just grizzly tough and nasty... Power Gel cuts through most heavy soil loads.
Sticky oil, oil, grease, petroleum based spots, adhesive, tar, chewing gum residue... Pro Solve Gel dissolves it all.
Add Encap-Spot to your spotting kit and you've got nearly every common spot covered.
This short video will give you a quick overview of just what you can accomplish with this simple trio of spot cleaning products.