Do you mean they would not eat it if you tell them what you put into your salad?
Then this is a great method!!!
Hide the color and taste for a while, and then you will tell them what they have been eating for a few months...
So they will have to admit they do not dislike it!
You can replace some of the vinegar, so the taste will not be noticed.
And do a lot of mixed salads, so they won't see it.