✅First, pay attention to the two following narrations:

1 عَنِ الْحَلَبِيِّ عَنْ أَبِي عَبْدِ اللَّهِ فِي حَدِيثٍ قَالَ: سَأَلْتُهُ عَنِ الرَّجُلِ يُصِيبُ ثَوْبُهُ جَسَدَ الْمَيِّتِ فَقَالَ يَغْسِلُ مَا أَصَابَ الثَّوْبَ

📚Al-Kafi, Vol. 3, p. 162

Translation: Halabi said: 'I asked Imam Sadiq (peace be upon him) about a person whose clothes touch the body of a deceased person.' The Imam said: 'He should wash what has touched his clothes.'

2 عَنْ إِبْرَاهِيمَ بْنِ مَيْمُونٍ قَالَ: سَأَلْتُ أَبَا عَبْدِ اللَّهِ عَنْ رَجُلٍ يَقَعُ ثَوْبُهُ عَلَى جَسَدِ الْمَيِّتِ قَالَ إِنْ كَانَ غُسِّلَ فَلَا تَغْسِلْ مَا أَصَابَ ثَوْبَكَ مِنْهُ وَ إِنْ كَانَ لَمْ يُغَسَّلْ فَاغْسِلْ مَا أَصَابَ ثَوْبَكَ مِنْهُ يَعْنِي إِذَا بَرَدَ الْمَيِّتُ

📚Al-Kafi, Vol. 3, p. 61

Translation: Ibrahim ibn Maymun said: 'I asked Imam Sadiq (peace be upon him) about a person whose clothes fall on the body of a deceased person.' The Imam said: 'If the deceased person has been given ghusl, do not wash what has reached your clothes from the deceased. But if the deceased person has not yet been given ghusl, wash what reaches your clothes from the deceased,' meaning when the body of the deceased has become cold.

✅According to the two above narrations, if a garment or cloth touches the body of a deceased person whose body has not yet become cold, or if the deceased person has been given ghusl, there is no need to wash the clothes. However, if the body of the deceased has become cold and he has not yet been given ghusl, it is commanded to wash it. Of course, the apparent meaning of these two narrations and some general principles that speak of something reaching the clothes from the deceased implies the presence of moisture, but since it is not explicitly mentioned in these two narrations, as a precaution, it should be washed even if there is no moisture and it is dry.

✅This washing is for when it touches the body of the deceased, and touching the clothes of the deceased does not have such a ruling.

✅Touching a deceased person, which requires ghusl, has different rulings.

✅Apart from the above matter, please also pay attention to the following narrations:

3 عَنْ عَلِيِّ بْنِ جَعْفَرٍ أَنَّهُ سَأَلَ أَخَاهُ مُوسَى بْنَ جَعْفَرٍ عَنِ الْبَيْتِ وَ الدَّارِ لَا تُصِيبُهُمَا الشَّمْسُ وَ يُصِيبُهُمَا الْبَوْلُ وَ يُغْتَسَلُ فِيهِمَا مِنَ الْجَنَابَةِ أَ يُصَلَّى فِيهِمَا إِذَا جَفَّا قَالَ نَعَمْ

📚Al-Faqih, Vol. 1, p. 245

Translation: Ali ibn Ja'far asked his brother Musa ibn Ja'far (peace be upon him) about a room or house that the sun does not shine upon and urine reaches it, and a person performs ghusl from janabah in them. He asked if it is permissible to pray in these two places if they have become dry. The Imam said: 'Yes.'

4 عَنْ عَلِيِّ بْنِ جَعْفَرٍ عَنْ أَخِيهِ مُوسَى بْنِ جَعْفَرٍ قَالَ: سَأَلْتُهُ عَنِ الْبَوَارِيِّ يُبَلُّ قَصَبُهَا بِمَاءٍ قَذِرٍ أَ يُصَلَّى عَلَيْهِ قَالَ إِذَا يَبِسَتْ فَلَا بَأْس

📚Al-Tahdhib, Vol. 2, p. 373

Ali ibn Ja'far said: 'I asked Musa ibn Ja'far (peace be upon him) about mats whose reeds are moistened with impure water. I asked if it is permissible to pray on them.' He said: 'When they become dry, there is no problem.'

The place of prayer

✅In several narrations, two of which were mentioned, it is permissible to pray on an impure spot if it has become dry and there is no moisture present. Therefore, assuming that a rug has become impure with something but is dry, permission has been given in the narrations to pray on it.

✅Regarding the purity of the place of prostration, please pay attention to the two following narrations:

5 الحسن بْن مَحبوب قَالَ: سَأَلْتُ ابا الْحَسَنِ عَنِ الْجِصِّ تُوقَدُ عَلَيْهِ الْعَذِرَةُ وَ عِظَامُ الْمَوْتَى ثُمَّ يُجَصَّصُ بِهِ الْمَسْجِدُ أَ يُسْجَدُ عَلَيْهِ فَكَتَبَ إِلَيَّ بِخَطِّهِ أَنَّ الْمَاءَ وَ النَّارَ قَدْ طَهَّرَاهُ

📚Al-Faqih, Vol. 1, p. 270

Translation: Hassan ibn Mahbub said: 'He asked Imam Kadhim (peace be upon him) about plaster that is fired with human impurity and the bones of the dead, and then a mosque is plastered with that plaster. He asked: 'Is it permissible to prostrate on it?' The Imam (peace be upon him) wrote in his own handwriting in response: 'Indeed, water and fire have purified it.'

6️⃣From Al-Halabi from Abdullah, he said: 'I saw him on the road to Mecca sometimes sprinkling water on the place of his forehead, and then he would prostrate on it as it was, while it was wet, and sometimes he would not sprinkle water on a place that he saw was clean.'

📚Al-Faqih, Vol. 1, p. 157

Halabi said: 'I saw Imam Sadiq (peace be upon him) on the road to Mecca sometimes sprinkling water on the place where he would place his forehead and would prostrate on it as it was, while it was moist, and sometimes he would not sprinkle water on a place that he saw was clean and pure.'

✅In some hadiths, like the two above, there is an implicit reference to the necessity of the purity of the place of prostration. Therefore, as a precaution, it is necessary for the place of prostration to be pure, but for other parts of the prayer area, if it is impure but dry and there is no moisture present, permission has been given in the narrations to pray in it.