Like many, I have struggled with #44 bulbs that won't burn, won't burn brightly, flicker, or worse, they only work when you are messing with them. As soon as you close the lid, they quit working again.
I have one of those little abrasive sticks that I twist around inside the socket, I have tried Scotchbright. ETC. After trying something else for some time, I think I have found the solution to help with flickering #44 bulbs.
The first thing I do is use a small rotary wire brush loaded into my Dremel Tool and spin it around inside the socket barrel to shine the insides up a bit. I also hit the spring loaded positive terminal at the bottom of the barrel and shine that up, too.
But the last thing I do--and this has worked for me 100% since I started doing this-- is I take a small round jeweler's file (Harbor Freight cheapies) and run in on the edge of the barrel area where the two tangs on the bulb skirt lock in.
My logic was to forget about the barrel being one big ground area for the bulb, but rather look at the bulb like it has three contact points which are the two locking tangs and positive button on the bottom of the bulb.
Running a small file on the edge gets rid of the last bit of corrosion in the socket and allows good contact. I also run a small flat file on the tangs on the bulb itself.
This has not failed me, yet.
Give it a try next time your are fighting your #44s.