I have a second hand petrol hedge cutter. I usually use hand shears to cut my garden hedges little and often but at this time of year I give them a more substantial cut back with the hedge cutter. I've decided to give it a bit of tlc before putting it away again for 12 months. The blades are covered in dried gunk and dirt. Do I clean with petrol, oil, turps, washing up liquid? I would lubricate afterwards and run til tank is empty. I have looked the manual up online and it has no care instructions.