Alton Brown has a good recipe for white trash mix. The ingredients include Cheerios, Chex, M&Ms, salted mixed nuts, small pretzels and white chocolate chips. The recipe makes approximately 25 servings and the preparation time is about 30 minutes.
To make Alton Brown's white trash mix, place 3 1/2 cups of Cheerios, 3 cups of Rice Chex, 3 cups of Corn Chex, 16 ounces of plain M&Ms and 2 1/2 cups of salted mixed nuts in a large bowl, along with 2 cups of small pretzels. Slowly melt two 11-ounce packages of white chocolate chips using a double boiler or a microwave, stirring occasionally and watching carefully so the chocolate does not burn. Pour the melted white chocolate over the cereal mixture, and fold the ingredients together until everything is coated with white chocolate.
Spread the white trash mix onto a piece of parchment paper, and allow it to cool. Once the chocolate is set, break the mixture into pieces. Store white trash mix in a sealed bag or airtight container.
White trash mix can use any combination of cereal, nuts and pretzels. One recipe from About.com omits the M&Ms and calls for 9 cups of assorted unsweetened cereals, 3 cups of salted nuts and 2 cups of pretzel sticks.