A Muslim's a Day Series 3-When we wake from sleep we should wash our hands thrice;it is Sunnah
Sahih ul Bukhari Hadith 162...kithab ul wudhu
عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ إِذَا تَوَضَّأَ أَحَدُكُمْ فَلْيَجْعَلْ فِي أَنْفِهِ ثُمَّ لِيَنْثُرْ، وَمَنِ اسْتَجْمَرَ فَلْيُوتِرْ، وَإِذَا اسْتَيْقَظَ أَحَدُكُمْ مِنْ نَوْمِهِ فَلْيَغْسِلْ يَدَهُ قَبْلَ أَنْ يُدْخِلَهَا فِي وَضُوئِهِ، فَإِنَّ أَحَدَكُمْ لاَ يَدْرِي أَيْنَ بَاتَتْ يَدُهُ ‏"‏‏.‏
Narrated Abu Huraira Rad'iyallahu a'nhu
Allah's Messenger Swallallahu a'lyhi wa sallam said, "If anyone of you performs ablution/wudhu, he should put water in his nose and then blow it out and whoever cleans his private parts with stones should do so with odd numbers. And whoever wakes up from his sleep should wash his hands before putting them in the water for ablution/wudhu, because nobody knows where his hands rested during night when he was sleeping