H2O2 decomposes slowly on exposure to light.
2 H2O2 (l) → 2 H2O (l) + O2 (g)
In the presence of metal surfaces or traces of alkali (present in glass containers), the above reaction is catalysed. It is, therefore, stored in wax-lined glass or plastic vessels in dark.
Urea can be added as a stabiliser. It is kept away from dust because dust can induce explosive decomposition of the compound.