Used oil, or 'sump oil' as it is sometimes called, should not be thrown away. Although it gets dirty, used oil can be cleaned of contaminants so it can be recycled again and again. There are many uses for engine oil recycling.

These include:

Industrial burner oil, where the used oil is dewatered, filtered and demineralised for use in industrial burners;

Mould oil to help release products from their moulds (e.g. pressed metal products, concrete);

Hydraulic oil;

Bitumen based products;

An additive in manufactured products; or

Re-refined base oil for use as a lubricant, hydraulic or transformer oil.

Thanks for this OP.
Hope some people will have something new to learn.

Umm