I like to attach fuel tubing to the carb and innox MX3 lubricant from the other end, one squirt will do it, that way the whole carb is flushed fully and does not gum up over time.
Spraying just into venturi is OK, but carb will still clog up eventually if left sitting for too long.
Like @gandalfnz said, but I just use ARO in the carb inlet, but I also use associated green slime on the HSN/LSN o-rings so they don't dry out. I put a few drops in the glow plug hole as well, then down the carb neck and in the carb fuel inlet, then turn it over a few times.