here i bring some sources when Indian explosives were found from Taliban
DAWN.COM | Pakistan | Indian-made IEDs recovered in South Waziristan
Indian explosives found from Lashkar-e-Jhangvi in Karachi, and India accuses of them all being supported by Pakistan.
Indian-made explosives seized in Karachi | Pakistan | News | Newspaper | Daily | English | Online
Indian explosives apprehended in Karachi Rupee News
When they find a shaving cream, soom wheat or other daily use stuff from terrorists attacking bombay, its called a concrete evidence and when explosives of Indian origin are found in Pakistan from Terrorists it is said they can be made from daily use stuff... funny
Now even if some explosives can be made from chemicals used in other daily use products, they are still strong evidence than a shaving cream or wheat which in no sense can be used for any evil purpose.
Pakistan and India have trade between them which touched 1.6Billion US Dollars in 2006-07, and in such a trade if some one finds a shaving cream or wheat then these are the very expected items and are widely available but explosive materials or chemicals related to explosives and only to be found from the terrorists is very unusual.
source for trade volume
Trade potential between Pakistan and India untapped