Backbudding on Yew

I have a large old yew with foilage all on the tips. I'm trying to encourage backbudding on old wood. I've pruned back hard for two years and not much progress. This the third year.

Would it help to clean off the flakier loose bark on the old trunks to encourage better backbudding?

Hard pruning should induce backbudding, as long as the tree is well established in its pot. Feeding it heavily and applying some lime also helps. You could clean off flaky bark if you want, but I wouldn't think that it inhibits budding.

It's easy- remove all old needles on bark that has turned brown. Some experts say go even further; up into the green bark