Soapiness

My new shampoo has a certain soapiness to it that makes it harder to wash out.

Source: wiktionary

You have no idea what a useful auxiliary the Black Cabinet of another Power can become — there is no better channel for false news, and in my short experience of the trade, I find oilmen and cheesemongers most indispensable factors of the diplomatic craft, colleagues I highly value, though I don't know what my high and mighty associates in the noble task of "disuniting" Germany would say, if I ventured to trespass on the sacrosanctity of these patented federal snorers (Bundestags Schnarcher) by assimilating my greasy grocers' boys, or my cheesemongering helpmates, to the bestarred and tinselled Excellencies of the Thurn and Taxis Palace, though they would give the former a point or two in soapiness and ignorance (Seifigkeit und Unverstand).

Source: wiktionary

Certain kinds of water when mixed with only a very small quantity of soap immediately produce a lather, and the water acquires that peculiar feel to the hands known as soapiness. Such water is termed soft.

Source: wiktionary