1$('#tag-id').removeAttr('style');
2

1$("p").removeClass( "myClass yourClass" )

1 $("div").removeClass("important");
2
3addClass() - Adds one or more classes to the selected elements
4removeClass() - Removes one or more classes from the selected elements
5toggleClass() - Toggles between adding/removing classes from the selected elements
6css() - Sets or returns the style attribute

1//removing css with jQuery. i.e: set to default 
2$( "#myElementID" ).css("background-color", "");//just blank it out

1$("#id").css({ 'background-color' : '', 'opacity' : '' });
2$(".class").css({ 'background-color' : '', 'opacity' : '' });
3//You can remove css by the above.

1$("#id .class").css({ 'background-color' : '' });
2
3/* 
4   As mentioned in the jquery documentation:
5   Setting the value of a style property to an empty string  
6   removes that property from an element 
7   if it has already been directly applied
8   e.g. $('#mydiv').css('color', '')
9*/