Google the phrase kill sticky for various snippets of code that can be placed on your bookmark toolbar.

In practice, you end up needing at least two or three different buttons to handle different sites. The one I usually use is

   javascript:(function(){(function()      
   {var%20i,elements=document.querySelectorAll('body%20*');
   for(i=0;i<elements.length;  
   i++){var%20p=getComputedStyle(elements[i]).position;
   if(p==='fixed'||p==='sticky'||p==='-webkit-sticky')   
   {elements[i].parentNode.removeChild(elements[i]);}}})
   ()})()