2.      If a person is unaware or forgets that their clothing is usurped and performs the prayer in it, their prayer is valid.

3.      If someone intentionally prays in clothing that contains any usurped element—such as a thread, a button, or anything else—their prayer is invalid.

If a person knowingly performs prayer in usurped clothing, the prayer is invalid (bāṭil).

If a person unknowingly wears usurped clothing, the prayer is valid.

If a person forgets that the clothing is usurped, the prayer is valid.

2.      Partially usurped items:

If a non-essential part of the clothing (e.g., a small thread, label, button) is usurped and the person intentionally wears it, it is precautionarily obligatory (iḥtiyāṭ wājib) to repeat the prayer with permissible clothing.

If one is unaware or forgets about the usurped part, the prayer is valid.

Prayer in usurped clothing is invalid if done knowingly and intentionally.

If the person is ignorant of the ruling or forgets the clothing is usurped, the prayer is valid.

2.      Small usurped components:

If only a minor part of the clothing (like a thread, button, or lining) is usurped, and the rest is permissible, then:

The prayer is valid if the usurped part is not independently considered clothing and has no significant role in covering the body.

If the usurped item is significant, or if praying in it is disrespectful, then it is invalid when done intentionally.

2.      If any part of a carcass is present with the person during prayer, then based on obligatory precaution, the prayer is invalid. However, if the parts are lifeless parts from a ḥalāl (permissible to eat) animal—such as hair, wool, horn, or bone—then the prayer is not invalid.

3.       Leather or hides from ḥalāl animals imported from non-Muslim countries, for which the process of Islamic slaughter (tadhkiyah) is uncertain, are not considered najis (ritually impure) and are regarded as pure (ṭāhir). However, one cannot pray in them.

·        If someone prayed in such clothing out of ignorance of the ruling, their prayer is valid.

·        If the importer is a Muslim and there is a reasonable probability that they investigated the issue of tadhkiyah, then praying in such leather is not problematic.

Prayer is invalid if the clothing is made from such a carcass, regardless of whether it is najis or ṭāhir.

2.Lifeless parts (e.g., hair, wool, feathers, horn, bone) from ḥalāl animals:

Valid even if the animal was not slaughtered Islamically.

3.Leather from non-Muslim countries (doubtful tadhkiyah):

Considered impure (najis) and prayer in it is invalid unless you are sure it was Islamically slaughtered.

If a Muslim imports it and there is a reasonable probability they verified the tadhkiyah, it is permissible to pray in.

4.Unaware of the ruling and prays in such clothing:

Prayer is valid, but if they knew the ruling and ignored it, the prayer must be repeated.

Invalid for prayer, whether the part is large or small.

Even if it’s dry or doesn’t transfer impurity, it cannot be worn in prayer.

2.Lifeless parts (e.g., wool, feathers, horn, bone):

Permissible in prayer, even if the animal was not slaughtered Islamically, as long as it is from a ḥalāl animal.

3.Leather from non-Muslim countries:

Treated as maytah, unless proven otherwise. Cannot be used in prayer.

If a Muslim sells or imports it and you reasonably assume investigation into its origin, prayer is valid.

4.Unaware of ruling and prayed in such material:

·        Prayer is valid and need not be repeated.

2. If pure moisture (such as saliva or nasal fluid) from a ḥarām animal—like a cat—is on the clothing or body of the person praying, the prayer is invalid, unless the actual substance has dried and its trace has been completely removed.
Likewise, if excrement of a ḥarām bird is on the body or clothing, the prayer is invalid—but if it is removed after drying, the prayer is valid.

3. If human hair, sweat, saliva, beeswax, pearls, or shells are present on the body or clothing of the person praying, the prayer is unproblematic.

4. If a person is unsure whether something is from a ḥalāl animal or a ḥarām animal, the prayer is valid.

2. Moisture (e.g., saliva or nasal fluid) from a ḥarām animal:

If it renders the clothing najis (ritually impure), the prayer is invalid unless it is removed.

If it is dry and does not leave visible residue, and is not considered najis, the prayer may still be valid—but precaution is advised.

3.Excrement of ḥarām birds: If it is najis, prayer is invalid.

If removed after drying and no visible trace remains, prayer is valid.

4. Uncertain origin (ḥalāl or ḥarām): If the person does not know whether the hair or material is from a ḥalāl or ḥarām animal, the prayer is valid.

5. Human items, beeswax, pearls, and shells: These are permissible in prayer.

2. It is forbidden for men to use gold chains, gold rings, or gold wristwatches, even for a short period (e.g., at the moment of a marriage contract), whether or not it is for adornment, and even if it is kept hidden from others. According to obligatory precaution (iḥtiyāṭ wājib), prayer with such items is also invalid.

3. Using gold for bone surgery or dental prosthetics by men is permissible and does not invalidate the prayer.

·  What is referred to as white gold:

If it is the same as yellow gold that has turned white due to mixing with other elements, it has the same ruling as yellow gold (i.e., forbidden for men).

However, if the amount of gold is so small that it is not considered gold according to common perception, then its use is permissible for men.

4. The use of platinum is also permissible.

5. If a man does not know or forgets that his ring or clothing is made of gold and prays while wearing it, his prayer is valid.

Khamenei’s Fatwa.

2. If the lining (āstar) of a garment—even part of it—is made from pure silk, then wearing it is forbidden for men, and prayer in it is invalid.

3. Wearing a garment when one is uncertain whether it is made of pure silk or something else is permissible, and prayer in it is valid.

4. For women, wearing pure silk—whether in prayer or outside of it—is permissible and unproblematic.

Note: In point 2, He says: Haram & invalid (if significant)