One way to soften the loafers' leather is to use wooden insert for initial couple of days. Insert the leather inside the heel area of the shoes while wearing it and leave it there for about 24 hours, or until you feel comfortable with the loafers.
Dampen an old newspaper page and then squeeze the entire quantity of the water. Then insert the paper inside the heel area of the loafers while wearing them and leave it there for about 24 hours, or until you feel that shoes leather is comfortable and fit to wear. Make sure the newspaper page is not too wet.
You can also rub petroleum jelly at back of the shoes, just outside the heel area. Do it until the jelly is completely absorbed. This will soften the leather and make it even fit and comfortable to wear. But make sure you only rub the jelly on the outer side of the loafers.
You can also apply a small amount of soap inside the heel area. This can soften the leather and make it comfortable to wear. Do not add water or anything else, as it will make foam and spoil the shoes. It will also make the shoes slippery.
Another and one of the most effective methods of making new loafers leather comfortable is to wear them in thick socks for the entire day, and do it for a couple of days until the leather is completely softened. However, also take into consideration the weather conditions and do not wear thick socks for a longer period of time in hot summers. This is also risky for loafers, it can damage the leather and also fade out its colour. Nevertheless, this is the safest way of softening the loafers leather, it does not allow any blisters to appear on the heel area, which is the most common and immediate effect of the stiff leather of the loafers. This makes wearing of the shoes further uncomfortable.