What are the conditions for a slight barrier (al-ḥā’il al-yasīr) concerning which Ibn Taymiyyah issued a fatwa, and is it a condition that its removal be difficult for it to be considered a slight barrier (such as paint), or is it permissible for it to be easy to remove (such as eye discharge)? And is it sufficient for water to pass over it without attempting to remove it?

Shaykh al-Islam Ibn Taymiyyah mentioned that a slight barrier is excused, and it is not a condition for it to be excused that its removal be difficult or burdensome. So, if it were something slight, like the dirt on the eye, the one performing ablution is not required to remove it.

However, it is more cautious to remove what is not difficult to remove, so that the one performing ablution can be confident that their duty has been fulfilled.