Hydrolats can be easily prone to fungal contamination. Store them in the fridge if you can and never leave the tops off the bottles whilst you are working.
Mix equal amounts with Rose Hydrolat / Hydrosol for a beautiful fragrance and amazing toner for all skin types.
According to the Cosmetic Ingredient Database (Cosing), the functions of Orange Blossom Hydrolat are:
Fragrance, Skin Conditioning, Tonic
To view more information, visit the Cosing Database here