Is the ghusl of janabah valid if slight traces of an adhesive substance remain, preventing water from reaching the fingertips after attempting to remove it?

If the substance prevents water from reaching the skin, then ablution (wudu) and ritual bathing (ghusl) are not valid in its presence, because conveying water to all purification organs is a condition for their validity according to the majority of scholars, whether the barrier is slight or not.

However, some scholars have made it easy for the slight (barrier) that is difficult to remove, by analogy with dirt under the fingernail. This is what Sheikh Al-Islam Ibn Taymiyyah chose.

Nevertheless, the more cautious approach is to adopt the view of the majority, and to repeat the prayers that were performed with the barrier present. One should strive to remove it during ghusl, but if one is unable to remove it, then it is excused, and it suffices to wipe over it with water.