Customize Play On Spotify Station

[musictexas]

How do I customize play on Spotify station?

I want station to be instrumental (no vocals), so I thumb-down every time I hear a vocal track on the Smooth Jazz station, although I may not always be around to do that.

Seems like there's a lot more vocals being played on Smooth Jazz than in the past.

Thumbs-down doesn't seem to have much effect.

How can I stop play of vocal tracks?