We have a small counter top "turbo oven" that we've had for over 15 years. Lately the plug has been getting uncomfortably hot if the oven runs for more than 5-10 mins. Recently we were cooking something that took about 20-mins and the plug got so hot that it would almost burn your finger. Even the receptacle felt hot. Not good!
So the first thing I checked was the receptacle to ensure none of the connections have loosened. This is a dedicated 20 amp circuit containing just one receptacle. The receptacle is a high quality tight fitting commercial grade Leviton 20 amp (i.e. good ole screw connections). Everything looked good in the receptacle with no signs of excessive heat. I checked the power consumption of the oven with a Reliance power meter it draws 12 amps on high which is in agreement with what is on the electrical tag.
Next - as a test I took my 2-foot 12 gauge adapter cable from my generator and used it between the oven and the wall. This would tell me if it was the receptacle getting hot or the plug on the oven. After just a few minutes the oven plug was quite warm while the receptacle was still cool. So now I know it is the plug.
The oven has a standard molded 2-prong plug attached to a short 16 gauge cord. I cut the molded plug off and replaced it with a high quality Leviton 15 amp plug. I then ran the oven for 20-minutes and both the plug and receptacle were literally cool to the touch!
Out of curiosity I cut the molded plug apart to have a look at the connection between the wire and the prong. As you can see below, even though the male prong is a thick clean conductor the wire is attached with just a small crimp connection. This plug did not originally get this hot but I think that over time this connection loses its integrity which causes resistance and heat build up. The prong gets hot which in turns makes the receptacle get hot. If let go it would probably eventually melt the plug and bad things could follow.
I'm posting this in case someone else finds a similar situation where you have a plug getting hot for no apparent reason.