my grandad built several scale models of engines, pumps, steam power machines with amazing quality and detail, when he passed away my dad inherited his traction engine and had it on display for years, but he was a heavy smoker and it needs cleaning and some touching up, im building a case to keep it clean (i don’t smoke but also stops grandchildren touching) any recommendations for this delicate job and any tips to do or not do would be great, added note, i live near Dartford and my grandad was near Lancaster so we only visited during school holidays, one year we saw several parts he was machining for the traction engine the next year he fired it up once with us all there and steered it around the garden patio! Then stripped cleaned and painted it and had it proudly on display