PETRARCH and FASSET have very low absorbency and therefore the attraction of atmospheric dirt is minimal. Generally rain water will provide sufficient cleansing. To keep panels bright and clean, the building owner should include an inspection in his annual maintenance schedule. A high pressure wash or scrubbing with a mild detergent followed by a clean water rinse, at high pressure, from the top down, using standard commercial cleansing techniques is all that is normally required. During installation or subsequently during building alterations, building site dirt and dust can contaminate the surface. This should be removed immediately. The following lists the most common contaminants and the recommended course of action for cleaning:

Drilling and Cutting Dust
After drilling or cutting, it is important to clean down the panel immediately, before panel installation. Use a sponge or brush and hot water with a mild diluted detergent and rinse with clean water, at high pressure, from the top down. If the dust is allowed to collect on the surface, it will become ingrained into the texture and will subsequently require more vigorous cleaning. Hole filling should never be done until the panel has been thoroughly cleaned.

Surface Scratches
When a scratch occurs, it will leave a light mark. This can be removed by gently rubbing with steel wool, "Brillo", or a similar pad using hot water with a mild diluted detergent. The indentation caused by the scratch cannot be removed and the use of the pad is to polish the damaged slate particles and return them to the body color of the material. In cases of extreme abuse, contact PETRARCH CLADDINGS for further recommendations.

Splashes of Plaster and Concrete
These are most easily removed before the plaster or cement has set. To clean, simply hose off with a jet of water and finally wipe down with a clean cloth. If plaster or concrete sets, then apply a hydrochloric acid solution (10%) and within 15 minutes wash with hot water with a mild diluted detergent. Finally, rinse with clean water at high pressure.

Paints
These are best removed when the paint is wet using the appropriate solvent and washing down with hot, soapy water. If the paint has dried, apply the appropriate solvent to the affected area with a nylon brush. It may be necessary to repeat this several times before all the paint is removed. Afterwards, thoroughly scrub the panels using hot water with a mild diluted detergent and rinse with clean water at high pressure, from the top down.

Tar, Creosote, Grease, Lacquer Paint
Clean the affected area with an appropriate solvent (see below) and if necessary, scrub with a nylon brush. Finally, wash down with hot water with a mild diluted detergent and rinse with clean water at high pressure, from the top down.

Pen, Pencil, Crayon, Lipstick
Use hot water with a mild diluted detergent and scrub with a nylon brush, finally rinsing with clean water. Pencil marks can often be removed with a simple eraser.

Caulking Materials
Using the solvent recommended by the caulking manufacturer, if necessary using a nylon brush, wash down with hot water with a mild diluted detergent and finally rinse with clean water at high pressure, from the top down. Structural silicone sealants must be removed from the panel surface immediately. If allowed to cure, they can leave a permanent residue.

Solvents
PETRARCH and FASSET are unaffected by the following solvents:

• Turpentine
• White Spirit
• Carbon Tetrachloride
• Toluene
• Xylene
• Paraffin
• Gasoline

The following solvents can also be used, but should be removed and the panel cleaned within 60 minutes:

• Methyl Ethyl Ketone
• Acetone
• Methylated Spirit
• Ethyl Acetate
• Trichlorethylene