Clean the balcony thoroughly with this model from Sealey. It has a weight of 6.8 kg, so it's small and easy to handle.
From OnBuy
Sealey PW1712 Rechargeable 12 Volt Jet Pressure Washer 17 Litre With Accessories
Tools4trade
Sealey PW1712 12V Rechargeable Pressure Washer 17L - Default