Personally I have a baby bath (£3 recycling centre), paraffin, couple of different size scrubbing brushes, and an old household cleaner squirty bottle filled with paraffin for that sort of thing, Jizer also does the trick,
tend to give mine a jet wash and steam clean but wilst the bike/engine is all in one peice .. not as easy once you taken it out du to things being open .
good ol scrubbinb brush warm water and washing liquid with a bit of elbow grease do.s the job ... also wd40 can be great for losening up oil and grime also petrol on a cloth works a treat .... best ever for cleaning hand grips and stains on light colord seats ect petrol on a rag come up like new