These are the two natural spas in Malaga province where bathers shouldn't mind the smell of rotten eggs

Those with a delicate sense of smell do not usually look favourably on this type of day out in Malaga province. However healthy they may be for the skin, sulphurous waters do not have the best of aromas for many would-be bathers.

Such baths give off an intense smell of sulphur. "They smell more like rotten eggs," complained the most negative bather in the group. It is only hydrogen sulphide, common to the spa baths of Vilo in Periana and La Hedionda in Casares. These are two of the places where, every summer's day, bathers from all over Andalucía come to take a dip that, in theory, is expected to help alleviate a skin problem. Or maybe they go just to benefit the skin in preparation for a long summer.

Both sites are over 150 kilometres apart by road. They are surrounded by wildly different landscapes, but both are characterised by sulphurous water springs that can be visited free of charge.

The best known and largest of the two is La Hedionda in Casares, whose name alone serves as a warning to bathers. These are not exactly sweet-smelling waters.

While it doesn't cost a penny to bathe there, in the summer season there are restrictions on access to limit numbers. In particular, a prior reservation is required to prevent a theoretically relaxing swim for family, friends or couples from turning into a stressful situation when you might be turned away.

The main purpose of this limitation is to avoid damaging this historic site, which has been in use since Roman times and today is popular with locals and visitors to Andalucía alike. However, the dome that protects the pool from which the slightly bluish waters originate is not nearly as old.

Nor should we give much credence to the story told about Julius Caesar and the healing of his soldiers' wounds in these waters. In some versions it is even said that they had herpes. It is neither one thing nor the other. It is not even true that the famous battle of Munda took place in what is now the province of Malaga. However, there are still those who want to feel as special as this historical figure and boast that they have bathed where Cleopatra's famous lover did.

Those who come to La Hedionda this summer - there are still a few places left - can even do so safely as Casares town hall, which is responsible for this site, also provides a lifeguard service.

There is no need to panic. It is apparently not dangerous at all, because its depth is little more than a metre and a half. There are even stairs to enter the waters, as in any municipal swimming pool. There is still even enough water to bathe in this year so you can still bathe without worrying about the severe drought just outside.

There are those who have booked online and come to spend the day equipped with much more than just a towel. Coolers with enough food and drink to feed an army, (perhaps thinking again of Julius Caesar's soldiers?).

However, to get there you must bear in mind that you will have to walk a path in full sun from the car park set aside for bathers. There are many signs warning of the penalties for those who even just try taking their car closer to the site. Your spa treatment could become a very expensive day out.

Access to the car park is from the Los Baños road up from the coast of Manilva. The neighbouring village is also offering this summer season a sulphur-stinking alternative at the Charca de la Mina, located via the same access road, but under the AP-7 toll motorway.

The waters have the same colour as those of La Hedionda because they come from there, although somewhat more diluted by the waters of Manilva river.

The other great option for a free bathe in sulphurous waters in the province of Malaga is much more modest and, in some sense, pretty wild.

It is in the hamlet of Baños de Vilo in Periana. It consists of sulphurous waters that spring forth at a cool 21 degrees. There is a small pool, barely one metre deep and two metres in diameter, where it is not comfortable for more than two or three people to bathe in at the same time - especially if they do not know each other.

You can get there via a narrow road from the road that connects Mondrón with Periana, just before reaching Periana village itself in the Axarquía region. However, it is important to bear in mind that the concrete lane along which you arrive is quite narrow, somewhat steep and has two-way traffic. On certain days it can be a real odyssey to enter via this road, although there is always an alternative not covered by Google Maps. Parking space is also in short supply. It was never going to be that easy to take a free curative bath.