Pesky stains should always be cleaned by hand in order to be removed properly. This can by done with a utility brush and scrubbing with soap and hot water.
When all the stains are removed, make sure to rinse everything off and flush away any detergent that can hide in the cushions.
A turbo nozzle can be very useful for those tougher jobs you may run into such as raw iron or old furniture frames that have never been cleaned. In these cases, rinse, apply detergent, and rinse again.