Thanks Eric and Rob for your responses. I will go ahead and wash that metal cone gently (I guess I better not put it in my '55 Westinghouse Laundromat).
Rob let me know if you have an extra 5AXP4 test picture tube, if you do I would certainly be interested in buying it and I'll search around for one locally too. I’ll keep you guys posted on my progress, thankfully there is a lot of open space under this chassis so there is lots of room to mount 10 new electrolytic caps.