battery overdischarge, possibly compounding issues.

[ar300d]

[B]update:saturday a.m. -- see stupidity below

[B]summary: [/

-completely discharged a basic duralast battery (was half a year old, probably started less than 50 times),
-no lights will come on,
-black terminal clamp on jumper cables began burning up in jumping process,
-began charging process with key in glowplug position for 20min @ at a 6amp charge (stupid)

details:
in my 83 300d, i certainly left the key in the position before turning on the glow plugs for a few days, and possibly a light or similar on. can't get so much as a light to come back on, even weakly. i know a hydrometer measurement, voltmeter would help in this case but i don't have one handy.

i tried to hook up cheap-ish jumper cables (thin looking clamps) between it and a running nissan murano. neg clamp on my car began smoking/melting whether it was grounded on engine block loop or on terminal, almost immediately and before any attempt to start (sidenote: considering getting heavy duty cables or two at once, but am worried about tiny looking murano battery and its electronics even being connected, would plan on disconnect during starting attempt).

if its relevant, my alternator brushes are worn down and i often have started using pliers to make the connection (below battery on wheel well), perhaps a few dozen times, 90% of starts in last 6 months.

checked fuses fwiw, they seem to be intact.

and fwiw, a few drives ago i had a brief electrical gremlin, at least blinker was double fast, i think dash warning lights were irregular in some way..

not likely relevant but -- last year had failing alternator that mightve stressed electronic systems? i likely abused the battery in that situation (at least an overcharge once and an overdischarge or two, replaced it after i stopped trusting it.)

questions:
-did i make this situation much worse possibly in any ways?
-is on 6amp charge now, any guess on when i should make an attempt at starting? (no lights/sound when charger was disconnected, car tested after an hour)
-should i just pick up a new battery and straighten this one out later?
-ive got aaa roadside; should i just have someone come out and try to jump it, test the voltage who knows what they're doing?


hopefully ill understand enough about these cars to help someone else here. any altruism in the form of responses is greatly appreciated. worst part was i was about to go on a sort of vacation from farm work.