cleaning motor oil off rubbermaid container

I recently found my husband spilled motor oil in the garage last fall and now I can't get it off the rubbermaid containers I have for storage. We tried bringing them to the self serve car wash and using the pressure washer, but many of them are still stained and still smell of oil. Any suggestions on how to get the remaining stain out? Thank you!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.