Investigation of the composition of chemical substances for stabilizing corrosive processes in historical iron objects is reported. Evaluation of the physical properties of the tannin solutions (density, viscosity, surface tension) as a function of concentration and type of solvent concluded that: 1) the best results, as concerns wettability and capillary rise of the corrosion products, were obtained for two-solvent solutions of tannin; 2) water is an indispensable solvent component as it intensifies the effect of the creation of iron tannates; 3) among the solvents examined (water, ethyl alcohol, methyl alcohol, and acetone), the best results were noticed for a composition of 1:3 water and methyl alcohol; 4) optimum concentration of tannin in solvents should not exceed 15%; more concentrated solutions are too viscous; 5) superficially active substances limit the wettability and capillary rise of tannin solutions; 6) the reaction of the applied composition should be slightly alkaline (pH 8-9)min these experiments ammonium hydroxide was used 7) the efficiency of treating the corrosion products with tannin solutions increases after multiple applications; 8) the gel formed as iron tannates provides a slight mechanical consolidation of the products of corrosion. The observations of wettability and capillary rise of the tannin solutions were carried out on special samples: 1) artificially corroded iron sheets deeply stamped, exposed to accelerated corrosion (in order to obtain physically and chemically homogeneous layers of stain, and the following solutions were used: 0.005% H₂SO₄, 3% NaCl and 5% H₂O₂); 2) samples of powdered rust formed in glass tubes as cylinders 5 cm in height, originating from iron corroded in natural soil conditions.