Simple Cleaning
wipe the surface with wet towel / wash away the sand and dust on or under the board with water

Deep Cleaning
Take apart the deck tiles (only need a few minutes)

If your balcony is about 18 sqft you can take up the deck tiles and start cleaning.
How To Clean Food Stains
Actually, oil stain is difficult to remove while been a longer time
please follow the following step
1.Wipe off stains with tissue
2. use warm soapy water to wipe the rest stains.
How to clean the mould?
NewTechWood has mould inhibitors that prevent mould growing on the inside of the board. Surface mould can still happen, however, it will never penetrate the board itself and is easily washed off.