I ask about the possibility to ask in Islam for the help of the devils to clear treasures of the earth.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. Allah, The Almighty Said: "And on the Day when He will gather them (all) together (and say): "O you assembly of jinns! Many did you mislead of men," and their Auliyâ' (friends and helpers, etc.) amongst men will say: "Our Lord! We benefited one from the other, but now we have reached our appointed term which You did appoint for us." He will say: "The Fire be your dwelling place, you will dwell therein forever, except as Allâh may will. Certainly your Lord is AllWise, All-Knowing."[6:128]. Exegetes (interpreters of Qur'an) state that the jinn benefit from mankind through being worshipped, and having sacrifices, vows, and supplications offered. Human beings, on the other hand, benefit form the Jinn through having their needs which they ask the Jinns fulfilled, though unveiling to them source events which the Jinn learn about in some distant places or overhear. They may also provide them with fabricated details and this is very common. Imam Ibn Katheer said that al-Hasan said: What is meant by 'benefiting from each other' is that the jinn give orders and mankind abide by them. Ibn Juraij said: People, in the pre-Islamic period of ignorance used to say when they rove the land and descend a valley: 'I seek refuge with the master of this valley (Jinn). So this is their benefiting from the Jinns and about which they argue on the Day of Judgement. As to the Jinn's benefiting from mankind, as it was said, it is the high esteem and respect they receive from mankind who glorify them and seek their help so much that the Jinn would say: 'we have dominated both mankind and jinn.' [Tafseer Ibn Katheer, 2/238] How beautiful are the details that Imam Ibn Taymiyah mentioned about the issue of Jinn and mankind! He said: What is meant is that the Jinn and mankind are in different affairs: - If a human being used to order a jinn to commit to what Allah, The Almighty has ordained such as worshipping Him, obeying His Prophet (peace be upon him), as well as ordering mankind to do so, then he is among the best endeared slaves of Allah, The Almighty and among the Prophet's vicegerents and deputies. - Whoever uses Jinn in permissible matters then he is as if he were using humans in permissible matters. If he instructs them to what they are ordained to do, forbids them from doing what is prohibited to them, and employs them in permissible matters, then he reaches the rank of kings who do the same. - Whoever uses Jinn in what Allah, The Almighty has prohibited such as polytheism, killing a human being unjustly or offending them in anyway such as causing them sickness, driving them to forget some knowledge, investing them in devilish things such as asking them to bring someone with whom ones may practice debauchery, then he is seeking their help in doing evil and transgression. If he seeks their help in disbelief, then he is a disbeliever, if he seeks their help in committing sins, then he is a disobedient; either rebellious or a sinful but not rebellious. [See Majmoo' al-Fatawa (11/307, 308)] Based on that, we may say, seeking guidance from Allah, The Almighty, that he who claims using Jinn is either a liar in what he claims and unable to do that, but claims so to frighten some people or to get some benefits from them - such as money or otherwise by means of sorcery or other ways - or he truly uses Jinn, in which case the following points have to be taken into account: 1) If he uses Jinn in a matter of obedience: such if he has a believer Jinn companion, from whom he receives knowledge and employs him to propagate knowledge to his fellow Jinn, or in helping in legal duties, then this is good and praiseworthy. This is viewed as calling to Allah, The Almighty's Path. Jinns once with the Prophet (peace be upon him), listening to Qur'anic recitation, and set off to their assembly of fellow Jinn as warners. Among the Jinn are those who are righteous, vigorous worshippers, ascetics, and scholars. A warner has to be worshipper and knowledgeable of what he warns of. [See the Fatawa of Sheikh Ibn Uthaimen in Belief (1/290,291) - though rough details are mentioned]. 2) If he uses Jinn in permissible matters, then it is lawful, provided he does so through lawful means. But if unlawful means are adopted, then it is forbidden, such as that the Jinn sets a condition that he does not serve him unless he associates others with Allah as partners such as offering sacrifice to the Jinn, bowing to him, prostrating to him, or if the connection with the Jinn was acquired via fortunetellers and sorcerers, etc. 3) If he uses them in prohibited matters such as robbing people's properties or frightening them, then this is unlawful. If the means was forbidden or involving polytheism, then it is forbidden or an act of polytheism, according to the situation. The majority of those who deal with Jinn and use them are in fact deprived of guidance, deviant from the right Path, perpetrators of major sins, abandoners of prayers or reluctantly performing them, close to filth and impurities, liars, falsifiers, duplicitous, unjustly consumers of others' money, seekers of and dealers in sorcery though forbidden, and use amulets and other unlawful, gibberish, and ambiguous formulae. Some of them even offer sacrifices to jinn or use milk in purifying their private parts (after answering the call of nature) at the order of Jinn, and other acts that incur disbelief. Such kind of people must be warned against and boycotted, since they are fabricators and deceivers. Allah knows best.