In the past, some visitors would write their names on the Wall, or based upon various scriptural verses, would drive nails into the crevices. These practices stopped after rabbis determined that such actions compromised the sanctity of the Wall. Another practice also existed whereby pilgrims or those intending to travel abroad would hack off a chip from the Wall or take some of the sand from between its cracks as a good luck charm or memento. In the late 19th century the question was raised as to whether this was permitted and a long responsa appeared in the Jerusalem newspaper "Havatzelet" in 1898. It concluded that even if according to Jewish Law it was permitted, the practices should be stopped as it constituted a desecration. More recently the "Yalkut Yosef" rules that it is forbidden to remove small chips of stone or dust from the Wall, although it is permissible to take twigs from the vegetation which grows in the Wall for an amulet, as they contain no holiness. Cleaning the stones is also problematic from a halachic point of view. Blasphemous graffiti once sprayed by a tourist was left visible for months until it began to peel away.