Mystery objects in a friends yard

It's mid October and a fall chill is in the air and the leaf colors are peaking along to coast of Maine.  Yesterday I visited a friend in Cumberland, Maine who let me spend an hour detecting on her property.  It was a pleasant day for digging and the dirt was very damp from recent rain.  I wandered all over the front half of her 1/2 acre lot and found a few odd items, some modern coins, and some larger pieces of scrap steel not shown below.

As I moved around the yard I was aware of the differences in the quality of the dirt.  The back lawn was dark, soft loam that was almost fluffy.  Below that was a layer of packed sandy dirt.  In other places, I found a lot of charcoal and nails, indicating that an earlier building may have burned down.  There is an old wood garage with a workshop shed in back, and another shed beside it.  Apparently a previous owner had worked on cars and was quite a craftsman tinkerer, so I expected to find odd items related to vehicle repair.

There were 2 mystery objects that seem vaguely familiar.  The first seems to be a radiator plug.  I think you would insert the plug an pull down the handle to expand the rubber plug that holds it in place.  If anyone can identify this - let me know:

update . . . So according to Frank on Facebook, its a snap-handle drain plug for a boat!

This knob-like item also seems vaguely familiar, but I can't place what it is:

update . . . some detectorists on facebook think it might be a "suicide knob" that people used to attach to steering wheels back before power steering was common.