Wikipedia
Toshakhana is a word of Persian or Sanskrit origin that literally translates into "treasure-house". In India, a toshakhana is a place where princes store "gifts and emblems of honor that they received for their posterity ... an archive of objects whose origin and receipt embodied his status and honor"
Under British colonial rule, the officials of East India Company were not allowed to accept "gifts" or "presents", often weapons or jewels known as khilat, from Indian rulers and their subjects. When procedure required that the officials received such a khilat, the official would deposit it in the Company's treasury (toshakhana). The objects were later used for exchange gifts with other Indian rulers, when it was deemed appropriate to enter an exchange of khilat.
Several countries have Toshakhanas. A Sikh Toshakhana is located on the first floor of the Darshani Deorhi, the gateway to the Harimandar. Bangladesh has a Toshakhana.