hondo,
First off, is the spray specifically designed for foam filters? If it is, be sure the filter is completely covered with the red (if the spray is, in fact, red). Do not soak the filter or it will drip down into the air box and will starve the engine for air. Just spray it on evenly and kneed it in while it is in a Zip-Lock bag or use disposable gloves to thoroughly cover the entire filter. That includes the inside. One thing you should remember is to use some good quality grease on the filter part that makes contact with the air duct so as to prevent dirt from getting into the engine. Note: If you use water soluble spray on the filter such as PJ1 you will need the solvent from PJ1 also to dissolve the spray when ready to clean the filter (water). Hope that helps.
Sid