Methods for preventing isotropic removal of materials at corners faulted by seams, keyholes, and other anomalies in films or other structures include use of etch blockers to cover or coat such corners. This covering or coating prevents exposure of the corners to isotropic etch solutions and cleaning solutions and, thus, prevents higher material removal rates at the corners than at smoother areas of the structure or film. Solutions, including wet etchants and cleaning solutions, that include at least one type of etch blocker are also disclosed, as are systems for preventing higher rates of material removal at corners formed by seams, crevices, or recesses in a film or other structure. Semiconductor device structures in which etch blockers are located so as to prevent isotropic etchants from removing material from corners of seams, crevices, or recesses of a film or other structure at undesirably high rates are also disclosed.