Oil Flushes or Engine Flushes

I might be importing an Oil Flush (sometimes called an engine flush - It is a detrgent that goes into the old oil and cleans the engine prior to draining the oil). It is a combination of petroleum distillate and detergents but I cant seem to identify the correct code to see what duties are involved. Any thoughts?

I think section 38 11 may be a good place to start looking…

Thank you for that. It does seem as though this is aimed at lubricating oils and/or fuels, whereas this product is essentially a cleaner?
Then when I drill down the 38 11 route there is also sorts of mysterious questions such as sulphur content, lead content tri-methyl-benzene content??? all of which are hard to fathom.
Thanks for the suggestion