Another vote for the iron.
I have used the iron on a 314 with no ill effects.
Here's the process. Get the iron hot and then lay a thick towel over the ding. Iron the spot with just the tip of the iron and for a few seconds at a time, always keeping the tip moving slightly. The whole process is maybe a minute or two, and that's taking time to check the ding in between heatings.
LWW
I have used the iron on a 314 with no ill effects.
Here's the process. Get the iron hot and then lay a thick towel over the ding. Iron the spot with just the tip of the iron and for a few seconds at a time, always keeping the tip moving slightly. The whole process is maybe a minute or two, and that's taking time to check the ding in between heatings.
LWW