For using on your oilskin garments. Use the block of wax by rubbing it with long, gentle strokes against the fabric, applying a thin, even layer.
To impregnate the wax into the fabric, use an iron set on single or double dot heat settings. Don’t steam. Alternatively you can heat the wax with a hairdryer.
The process can be repeated several times to improve the water repellent performance, especially the shoulders are rear of jackets, knees of trousers.