A Non-Muslim's Endowment
An endowment set up by a non-Muslim — whether among the people of the book or not —is valid in cases it is valid to be set up by a Muslim. Therefore, it is obligatory for the trustees to act according to the provisions laid down in the endowment deed. 

Temporary Ḥabs
If a person makes, for a certain period, his land ḥabs according to the shar‘ī rules and regulations, the ḥabs is valid. Thus, all shar‘ī provisions should apply. After the duration of the ḥabs comes to an end, the land should revert to the ownership of the owner and be treated like his other properties.

How to Endow a Masjid
Building the place with the intention of rendering it a masjid per se is not sufficient to realize the endowment unless they utter the endowment formula or hand it over to the worshippers to hold prayer there. Rather, it remains as the property of the landlord and he is, therefore, free to do with it whatever he wishes.

How to Endow a Ḥusayniyyah    
Raising money for buying something for a ḥusayniyyah in itself does not amount to endowment. However, after purchasing it for the ḥusayniyyah and making them available for use at the premises, a de facto endowment comes into force, i.e. without the need to pronounce an endowment formula.

To Use the Facilities of a Masjid for Religious Ceremonies
 The permissibility of using the facilities of the masjid for special mourning events and the like is dependent on the conditions of the endowment or donation of those facilities as nadhr for the masjid.

Personal Use of a Masjid's Electricity
It is not permissible to make use of the electricity supplied to the masjid for private purposes. Nor is it permissible for the administration of the masjid to grant such permission.

To Sell Property Endowed for a Masjid
If it is absolutely not possible to use the property — that is already endowed for a masjid — in the same masjid, they may use it in another masjid. If that proves impossible, they should use it for the public interest. But, if making use of it is not possible but through selling, they can sell it and spend its money on the same areas in the order mentioned above.

Spending a Masjid Money
It all depends. If by a masjid’s money it is meant people’s contributions, this money should be spent on the areas it is contributed for and spending it on other purposes depends on the consent of the contributors. Thus, if it is confirmed that they agree on such spending, there would be no problem. But if you mean the income of the property held as a waqf, then it should be spent on the same areas shown in the waqf paper.

To Change a Waqf
Except for special cases, one is not allowed to sell, buy, or change a waqf and it should be used for the purposes it was endowed for.

The Trustee's Wage
The trustee of an endowment, whether appointed by the endower or the judge, is entitled to receive normal wages from the proceeds of the endowment if no specific wages is determined by the endower.

Trusteeship Continuation  
If someone is appointed as the trustee of an endowment by a marji', he will remain as its trustee after the demise of the marji'. However, if he is the marji''s agent/agent of agent to run the endowment's affair, his agency is invalidated by the marji''s demise or cancellation of the agency of the first agent.