Exceeded my expectations!!! After 4 years the TimberTech decking became quite stained with mildew residue spots created by rain. I power washed it a year ago however it did not remove the deep stains. Two weeks ago I used the Corte*Clean, following the instructions carefully! It really worked - the stains are gone and the deck looks nearly as it did when first installed!!! Note that after applying the Corte*Clean solution on the deck, letting it absorb for 10-20 minutes, scrubbing it with a brush, I power washed the deck, instead of just rinsing with a hose. The hose rinsing alone left some stain residue (though much less than after just power washing, but still noticeable) - so my recommendation is to power wash to rinse!!! One happy customer ...