What brand name and model are your
harp(s)? What key is factory-installed
on your slide chromatic(s)?
Are the F-F# valves gurgling only on a
key of C chromatic, or on other factory-
installed keyed harmonicas, too?
I've played the F-F# valves on a key of
F harp, G harp (both Hohner 270s); and
key of C harp (Hering 12-hole Baritono).
No problems with any of these harps.
The paper clip; pin; methods with
finger/thumb pressure are discussed
in the instructional chromatic harp
book, "Make Your Harmonica Play Well",
by Doug Tate, former SPAH President.
The book is currently published by
Centerstream Publications. It's clearly
presented.
If, like me, you learn by reading & doing,
the book covers many other topics for
harmonica maintenance and repairs.
Best Regards, Stay Valved
JB