I've thought more and more shining the ball is more to do with managing the rough side than shining. Most wickets in England allow a ball to retain it's shine with minimal shining. The trick is actually to create a proper rough side and create the imbalance that leads to drag in the air (between the 2 sides).
Couple of examples, I remember taking a ball in a game that was completely roughed up on both sides on an abrasive deck. Within a couple of overs I was getting it to swing round corners through soaking one side in sweat and shining. Taking this to the extreme, once in my 30 odd years, I came across reverse swing. I remember using a cheap indian ball for a Sunday game. On our deck, the ball was wrecked in no time. Everybody looked at it and thought "rubbish ball". When the oppo used it (one ball per game), about 10 overs in this lad came onto bowl and it started hooping down leg. The guy kept muttering "I normally bowl outswingers" and eventually got taken off. I took the match ball and used it in the nets. It did reverse even at my gentle pace.
Manage the ball yes, but get some wear on it if you want it to swing.
Just to go back to the opening post, I remember our 20 over old match ball getting hit into a puddle. The ball got soaked but 2/3 overs it really hooped. Soaking in water can help create an imbalance as the water adds weight and mass to the ball.