It is not obligatory to spend half an hour in the bath. You should bathe for as long as necessary to soften any scabs and ensure your skin is clean. When a bath is not available, a long shower is sufficient in preparation for immersion.

The key is to make sure that you have done a thorough job of chafifah. This means ensuring that all dirt and foreign objects are removed, that warm water has gotten to all folds and crevices, and that your hair has been washed with warm water and thoroughly combed.