Measurements: 2.5 Litre Our formula can be used on a multitude of surfaces such as patios, fencing, driveways, roofs, gutters, artificial grass & caravan. As Wet and Walk Away requires no agitation you can be sure that no damage will be caused in the cleaning process. You will see quick results in a matter of a few days. Cleaning paving slabs on a patio can be difficult if you are not using the best patio cleaner for the job. Cleaning natural stone patios in particular can be challenging as the surface of sandstone or limestone paving is the perfect environment for the spread of moss, algae and mould on a patio. Using an effective patio cleaner is a must if you want to make your paving slabs or block paved patio look like new. Our formula with its special active formula safely and effectively removes green staining with ease.