Every time a student uses it incorrectly, I quickly correct them. "You mean simplify this expression", or the like, and then go on to answer whatever question they meant to ask. Furthermore I verbally check in on the exact definition of "solution" multiple times. Some book exercises that I hand out occasionally have warm-up questions on this topic (Bittinger Intermediate Algebra, Martin-Gay Introductory Algebra). And every time I present an exercise on the board I always include a formal written direction, e.g., "Divide the polynomials and check", etc.
This encourages, but does not entirely solve, the problem. I suppose the next level of escalation would be to include it in some multiple-choice quiz questions, but to date I don't think its priority is high enough to bump another item out of my quizzes. The truth is students at this level rarely put effort into an issue unless points are on the line.