DEB Janitol Rapide diluted around 4:1 with water.
Apply witha trigger squirty bottle & agitate with a stiff brush. Re-apply as required.
As this is a caustic product, wear gloves & eye protection. I generally wipe off & dry with paper towels.
This works very well on coolant residues – at my previous employment (CNC machine tool rebuild & retrofit) we went almost exclusively to water base caustic cleaning solutions as they worked more quickly & more effieciently than solvents & didn’t cause much paint damage. Currently using the DEB product to clean machines bought at auction before starting to use them in production (machining exclusively graphite – sticky, oil surfaces attract the dust).
Caustic multi-surface kitchen cleaners probably work as well & available in ready-to-use bottles from supermarkets – I generally have a bottle of Mr Muscle glass cleaner in the office for cleaning monitors etc. and it is effective when used for other small cleaning small jobs. A bit expensive for the bigger machines, though.
Be wary of gunwash – nasty stuff, gets into your system through your skin even when wearing gloves. Also highly inflammable with a low flashpoint. Meant for cleaning painting equipment & best reserved for that IMHO.