Is there anything to be concerned with this picture?
That junction box had a fire.

It melted the lower side of the box. Probably nearly burned down the house.  

As for the cause of the fire, I see plain wirenuts and aluminum wires.  Obviously this wire-nutting is contemporary to the fire, but the apple doesn't fall far from the tree, eh? This is probably the classic situation of faulty terminations on aluminum wires, but for all I know, the aluminum wires were innocent bystanders and this was an incompetent wire-nut job on copper wires.  Aluminum wires need terminations rated for them.  Not having those is what caused the problem in the 70's.  

So replace that box with a metal one less likely to catch fire; I recommend a 4-11/16" square steel box with a 1-gang or 2-gang mud ring, as you need a lot of room for 4 cables, grounds+clamps, and a receptacle or two. (5 sq.in. Each). That box was surely overstuffed if it had a receptacle.  

Evaluate wiring throughout the house

Particularly aluminum wiring.   You want to see if wiring like this is typical in this house.  If it is, we need to emplace some strategies ASAP to protect the house.  

The first line of defense against shoddy wiring is AFCI breakers.  These listen to the wires for arcing faults (like the one that started that fire). That classic GE panel is still fully supported (mostly; GE made some changes to bus stabs that might  affect you; ask a new question about that).  

AFCIs do not come in double-stuff breakers, so noting the use of a few double-stuffs, you might need to combine a few circuits in order to fit AFCIs.  It's worth it.  

That service panel

I do not like the rust pattern on it.  It makes it look like the humidity source is on the inside, and I would expect if you took that cover off, you'd find a sea of rust.  Not cool.  

Also, if this is a "Rule of Six" (six main breakers) panel, that is a showstopper. Get rid of it.  

I would stay with GE, nothing wrong with it.  However, if space is a premium, use Eaton CH or Square D QO (Eaton has cheaper breakers, but QO supports generator interlocks better). 

Also, plug the humidity source! Probably a conduit pipe that goes outside.  

Grounding

There is no such thing as a self-grounding box.  Boxes cannot reach through the mystical aether and obtain a ground.  They can pick it up from ground wires, but here you have the problem that these are aluminum ground wires, and only a limited number of devices can splice to them.

It might be fairly naughty Codewise, but you could buy accessory ground bars for panels, cut them up, and then fasten them down in the back of a metal junction box. That may be cheaper than using an Alumiconn to pigtail to a metal box.