Question
Is it permissible for a sick person who cannot get up from bed to perform ablution to do tayammum by striking the wall?
Answer
I say, and with God's help: It is valid to perform tayammum on dirt, stone, or dust. If the wall is not painted, it is permissible; if there is visible dust on it, it is permissible; otherwise, one must perform tayammum on a piece of cloth that has visible dust on it. And God knows best.