We report on studies of non-toxic scintillating liquid useful for large surface detectors. Arrays of liquid scintillators offer a rather simple tool for detecting charged particles traversing a surface and tracking their path through a defined volume. Insertion of wavelength shifting fibres along the liquid scintillating containers significantly improves the light collection at the two ends of the scintillators. We have demonstrated that we can achieve timing resolution of O(1 ns) allowing good spatial resolution. Liquid scintillators with fibres read by Photo-multipliers or SiPMs provide an inexpensive alternative technology which suits well the requirement of the MATHUSLA experiment tracking system.