"Reliable sources from NASA USA and some world organizations - please be aware that starting from today until 28th April, avoid getting wet in the rains as volcano explode in Iceland, acid rains are highly probable to occur. The acid rains will cause skin cancer."
If I recall my geography lessons, sulphur is one of the main contents from volcanic spews. So if mixed with rain water, you get sulphuric acid which of course, burns the skin and erodes metals, etc.
You may ask since Iceland is so far away, what has volcanic ashes got to do with Malaysia? The world is round and spins. The volcanic ashes get carried by the winds. (The eruption of Krakatoa in Indonesia in 1883 caused ashes to be in the air globally for more than 1 year. Acid rains were also reported then. Temperature worldwide dropped by 1.2C and only returned to normal in 1888.)
So there is some truth in the sms and advice is to avoid too much of outdoor activities, and not just the rain.