I received the following useful comment on this topic from a doctor whose method is a bit different from the one that my doctor recommended. I think that it is worth reading.
1. Before you start the home remedy, please see a podiatrist or foot doctor specialist. I have never heard of using a hot water bottle; I usually suggest cold water. The effect of using a hot water bottle would stretch the plantar fascia (heel spur) certainly, but it would take a long time to properly heal the plantar fascia, depending on the extent of the injury. I have a great interview with Dr. Robert Schleip for the blog that discusses plantar fasciitis (heel spur)
Thank you for this comment. I saw a reference to using cold water on some websites and in these the water in the bottle was frozen. There is one other thing that I would like to mention. The link to the doctor’s blog has a useful article on treating foot troubles, but it mentions yoga and I have read to be careful of using anything that has connections with pagan religons and unfortunately Yoga has. As far as I know Pilates (exercises) doesn’t have this connection. I take the point though that stretching is a useful tool in healing.
The reason that it is not good to use Yoga which has its roots in a pagan religion is because it can be a pathway to the occult.