[Boatanchors] Regen selectivity improvement methods?

[Howie WA3MCK]

Colleagues,

Generally, what can be done to improve the selectivity of a regenerative
receiver?

For example, I vaguely remember a modification for the Heathkit "Sixer"
that included  "tacking" a  22 Meg Ω resistor to one terminal of the
regeneration control pot. Or, am I mistaken?

Tnx es 73 de Howie WA3MCK