Any state that is party to either the Anti-Personnel Mine Ban Convention or the Convention on Cluster Munitions has a specific deadline for completing survey and clearance on its own territory and on foreign territory it occupies.
Disarmament law is a specific branch of international law. States become party to a disarmament treaty, such as the Anti-Personnel Mine Ban Convention or the Convention on Cluster Munitions, by signing and ratifying the treaty (or simply acceding to it, which has the effect of signature and ratification in a single act). The act of ratification or accession is performed by an authorised representative of the state sending an instrument (a letter) to the treaty's depositary, the United Nations Secretary-General clearly setting out the state's intention to become party to the relevant treaty.
Another source of international law is custom. A customary international legal rule is one that has become binding on all states because of a general practice among states that is regarded as legally binding. An example is the prohibition on torture. There has not yet been a study of what disarmament rules have become customary international law, but the customary law duty to respect and protect the right to life demands that each state clear explosive contamination from its territory as soon as it is possible to do so.