There are 3 important things that could be proven in a day with marginal resources (thus those 3 things could not be hidden. No way):

• chemtrais: those could be detected remotely using all sorts of spectroscopy + sampling on the ground
• anti-cancer magic cures: by using the cell cultures, it could be easily proven if it works in just a perfect condition (you put some drops on various cancers). The composition could be found in a day using various HPLC related methods. And all the leading compounds could be compared with the proven substances (either similar or same) and found in a various database. This is the basic flow for MSc/ PhD thesis. If there is a simple cure for cancer - it could not stay hidden for more than a month.
• homoeopathy: dilute --> find a stronger signal. Or... Put it on the cells --> dilute --> prove that it actually gets stronger