Nope, it was a clean as a whistle. To be fair I’d blocked the holes with dowels and some wax. I didn’t know at the time about those rubber plugs the blasters use. I dried it throughly, blew it out with compressed air, then blew hi pressure water/detergent through it then repeat. I made sure that the head was dry by storing in the airing cupboard for 24 hours each time. I also did a little probing as you have described. I took the bungs out as I’d read somewhere about the risks of leaving unwanted medium in there. TBH, if I ever do another SOHC I’d just go for the bung, block and clean process.