Article: Less surface area on the gum means less gum to remove. Lanacane is available at drug stores or grocery stores. Lanacane contains Ethanol, Isobutane, Glycol, and Acetate. This group of chemicals speeds up the release of the gum. A knife with a good edge might work better, but it has a higher chance of cutting through your fabric.

What is a summary?
Remove as much of the gum as possible. Apply some Lanacane to the gum, waiting 30 seconds or less. Scrape gum with a blunt knife. Wash as usual.