"Put dust on your writings, because it is better, and dust is blessed (being humble in correspondence brings good results)."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ تَرِّبُوا صُحُفَكُمْ أَنْجَحُ لَهَا إِنَّ التُّرَابَ مُبَارَكٌ