until your lifting a decent amount of weight that might affect your main workout I see nothing wrong with using them as a warmup. The high frequency is what you need to become competent anyways. Also make sure your doing full cleans, power cleans are a nice variation but if your serious about learning olympic lifts then you need to prioritize a full clean.
So basically just rotate the lifts, one day use clean and jerk for the warmup and the next use snatch. If the weight your using starts getting close to that 50% range of your squat then you should start thinking about using some more intelligent programming.