Product for synthetic hair

While I'm growing my hair long enough to be able to do extensions, I've
been wearing good qualilty synthetic hair wigs. I take them to my local
wig shop for regular cleaning and notice when they are freshly cleaned
they are very soft and shiny. After a few wearings the synethetic hair
starts to stiffen and become less shiny. I was given a silicone product to
spray on them every few wearings but find that this only dulls the shine
on the wigs even further. I want to leave my wig cleaning to the
professionals but am wondering if there is a product that works for
synthetic hair that one can apply to dry hair between cleanings to keep
the hair soft and shiny.

Yep, Sherrie, they steam-clean them. I'm just wondering if there is
something to use between cleanings that would keep them soft and
shiny. It is amazing how the texture of the hair changes from kind of stiff
to soft and smooth. I'd consider just getting them cleaned more often,
but the place is a bit of a drive and they take several days to have the
wigs ready when I bring them in. I was hoping that some of you who
have used synthetic extensions might have a trick for keeping them softer
between cleanings. The wig shop only sells their own line of care
products, and I'm not at all impressed by them. I might even consider
washing the wigs between cleanings if I had products that made them
soft again after washing.