How can I remove the gloss on a select element in Safari on Mac?

@beanland; You have to write

-webkit-appearance:none;

in your css.

read this http://trentwalton.com/2010/07/14/css-webkit-appearance/

Using -webkit-appearance:none; will remove also the arrows indicating that this is a dropdown.

See this snippet that makes it work across different browsers an adds custom arrows without including any image files:

select{
	background: url(data:image/svg+xml;base64,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) no-repeat 95% 50%;
	-moz-appearance: none; 
	-webkit-appearance: none; 
	appearance: none;
    /* and then whatever styles you want*/
	height: 30px; 
	width: 100px;
	padding: 5px;
}

<select>
  <option value="volvo">Volvo</option>
  <option value="saab">Saab</option>
  <option value="mercedes">Mercedes</option>
  <option value="audi">Audi</option>
</select>

2019 Version

Shorter inline image URL, shows only down arrow, customisable arrow colour...

From https://codepen.io/jonmircha/pen/PEvqPa

Author is probably Jonathan MirCha

select {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  background: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='100' height='100' fill='%238C98F2'><polygon points='0,0 100,0 50,50'/></svg>") no-repeat;
  background-size: 12px;
  background-position: calc(100% - 20px) center;
  background-repeat: no-repeat;
  background-color: #efefef;
}

Sorry to pile on to an old item. I found partial answers to my questions here but had to do some work so I wanted to share my results for the next person.

I ended up using the same approach as the other contributors, but with a few tweaks to fix the following

1. Long text was covering the arrows in the other solutions
2. The image being used was a somewhat old and ugly up/down combo arrow.

The below will give you a working solution with the above issues fixed. Note: I used a white arrow for my use case, you may need to change the color of the arrow for yours.

here's a preview:

select{    
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  background: url(data:image/svg+xml;base64,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) no-repeat 101% 50%;
  padding-right:20px;
}

Check out -webkit-appearance: none and its derivatives. Originally described by Chris Coyer here: https://css-tricks.com/almanac/properties/a/appearance/