The CRI Certified Seal of Approval program was launched in 2004 to test the cleaning effectiveness of spot removers, pre-spray, and in-tank cleaning chemicals. CRI uses scientifically accredited cleaning standards to identify which cleaning solutions work best. To earn the Seal of Approval, spot removers and pre-spray/in-tank cleaning solutions are tested on the following criteria:

• Overall cleaning effectiveness — This ensures that the product removes soil and spots better than plain water.
• Rate of resoiling — This ensures that the product does not attract dirt to the cleaned areas faster than the rest of the carpet.
• pH — A more neutral pH ensures that carpet dyes and fibers are not adversely affected.
• Surface texture change— The product must leave the carpet pile minimally changed after repeated cleanings.
• Optical brighteners — None are allowed, as they can leave some patches of carpet lighter than the rest.
• Colorfastness — Products must not be so aggressive that they cause a color change in the carpet.

Water is used as a control variable. This means that the performance of a product is measured against the performance of water, for all of the criteria outlined above.