Adding and removing style attribute from div with jquery

I've inherited a project I'm working on and I'm updating some jquery animations (very little practice with jquery).

I have a div I need to add and remove the style attribute from. Here is the div:

<div id='voltaic_holder'>

At one point in the animation I need to add a style to it:

<div id='voltaic_holder' style='position:absolute;top:-75px'>

I've searched around and found the .removeAttr() method but I can't see how to add it, or even remote parts of it (like the top:-75px only).

Thanks,