Where there is no fixed judgement, the traditions and conventions of community are to be referred Sahih al-Bukhari 2210
Arabic hadith text
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ حُمَيْدٍ الطَّوِيلِ، عَنْ أَنَسِ بْنِ مَالِكٍ ـ رضى الله عنه ـ قَالَ حَجَمَ رَسُولَ اللَّهِ صلى الله عليه وسلم أَبُو طَيْبَةَ، فَأَمَرَ لَهُ رَسُولُ اللَّهِ صلى الله عليه وسلمبِصَاعٍ مِنْ تَمْرٍ، وَأَمَرَ أَهْلَهُ أَنْ يُخَفِّفُوا عَنْهُ مِنْ خَرَاجِهِ.
Translation
Narrated Anas bin Malik
Abu Taiba cupped Allah's Messenger (ﷺ) and so Allah's Messenger (ﷺ) ordered that a Sa of dates be paid to him and ordered his masters (for he was a slave) to reduce his tax.