A test kit for testing substrates for soluble salts including a test sleeve (10), a pre-measured volume of solvent solution, and a soluble salt measuring device (30). The test sleeve includes a generally tubular body (12) with a closed end (14) and an open end (15). The open end includes a flange (17) defining an aperture (18), and an attachment member (13) coupled to the flange for removably securing the testing sleeve to a substrate.