I just cleaned / lubed all the sliding door guides a few weeks ago.  I used
"White Lithium Grease" which is a good choice for this purpose.

For example:
http://www.amazon.com/Panef-Corp-GS-20-White-Grease/dp/B000BXOFV6

Your local home depot or equivalent should have it,not sure about the local
FLAPS.

I put it on the bottom slide / roller, and also inside upper track and the
rear track.  Previously there was a "metal on metal" sound coming from these
areas, a bit of this grease quieted the whole thing down.  I used very
sparingly, since I didn't want a whole bunch of extra grease hanging around
collecting dirt, so a little already made a difference.  I think using even
more grease would provide even less noise.  To grease the rear roller, I
didn't have to remove the cover, just put the grease in the right exact
place with the 2 finger feel method:  one finger with grease on the tip, the
other finger clean, as a guide to find the right places.  The bottom roller
is a regular once-a-year maintenance area for me, clean and replace a bit of
grease.

Reason for doing this?  I installed FatMat inside the sliding door, and
wanted to quiet the rollers at the same time.

Roland

On Mon, Jun 6, 2011 at 8:22 AM, Susie <dingham605@aol.com> wrote:

>  Hi All-
>
>  We cleaned and lubed our sliding door a few weeks ago-- it's got a real
> unpleasant sound now, so I think we used the wrong type of lube. Whats  the
> recomendation from  listers as far as the best  type of lube?
>  thanks in advance!
>
> Susie
>