I must agree, sick weldding still has a place in the right eviroment.
Shipyard or perhaps in the field where shielding the weld area from the eliments is either impossible or impractable
Ark welding is more tolerant of rust, paint & other impuritys, as any shipyard or plant repairer will tell you.
That said, my local dry dock ( Former employee ) is now making extensive use of mig welders for general repairs.
When I was last working there in the late 80's, they didn't have a single mig welder
Mind you one of the last dry docks in the country to be using rivets
Back to the subject of stick welding.
difficult slag removal can somtimes be an indication of weld undercut. This occurs when the edges of the weld bead penetrates the parent metal too deeply & leave a small crater. ( Main culprits are too many amps or poor technique ).
Under cut is very undesireable & is seen as a structural weakness
The slag more often than not will peel off as the weld cools, choice of electrode also makes a difference.
The slag on some non-rutile electrodes can be a real pain to remove.
When you strike an arc do it a couple of centimetres upwind of the direction that you are intending to go, when the arc has fully established slowly move to your start point. don't worry about splatter, the welding arc will soon burn that out of the way. This way, you will eliminate the risk of slag inclusion at the weld start point.
Yes, at the end of the weld, just draw back a couple of mm & pause for a second or so, that'll fill the crater at the end of the weld . Not needed if you are simply changing for a new electode.