Mga sis okaya [textspeak!] ba to designate the sponges used for a particular place. Ayaw ko kasing all around ang sponges. 
Okay ba yung ganito?
Master bathroom toilet sponge -green
cleaning cloth -green
Kids bathroom toilet sponge -yellow
cleaning cloth- yellow
at iba pa?
I do not allow sponges and other cleaning implements to "travel".
So the sponge in any 1 kitchen sink, stays there until it dies -- it is never transferred elsewhere.
It also helps, IMO, to have a variety of "sponge-alternatives" This has helped my cleaners and other helpers remember what to use where.
If the cleaning implements/alternatives make life easier for them -- they easily remember your rules.
For example,
for the bathroom -- the maid uses those body nylon scrub balls (sorry, the name for that the escapes me now -- it is those cute colored puffy scrunched up balls generally used for body scrubbing during showers/baths) for the sink and its interior & top surfaces.
For the bathroom sinks' exterior/body -- they use thick sponges.
(Now take note that these thick sponges are good for big surfaces/stuff -- not for kitchenware.).
For the toilet bowl -- of course, there are the long-handled brushes that are stored in their own containers by the toilets.
For the body and seat surfaces -- the cleaners use those always-damp chamois cleaning cloths.
For the floor -- we have those dishcloths commonly sourced from Baguio which are all over the tiangges here in MManila.
If the bathroom walls need cleaning -- they may use the thick sponges and Baguio dishcloths.
(In each bathroom -- there is a rectangular 4-inch high plastic container of cleaning supplies and a handled tabo containing the sink scrubbers and chamois cloths, etc. So, no traveling of sponges/alternatives from room to room. )
For the kitchen sinks -- I buy those regular-sized soft sponges from the supermarket. Nobody uses sponges on the counters. Either the Lysol wipes or the designated kitchen counter dish cloths are used (I color code the dishcloths used as trapos, not the sponges).
So there -- each bathroom/powder room has its own sponges/alternatives and basic cleaning supplies.
My lavandera controls the inventory of spare sponges and sponge-alternatives (also the detergents, etc.) But at anytime, it is easy to have any spong/alternative that "died" replaced.
So given that the above "rule" prevents the "traveling of sponges" --
the other "rule" that enforces that no-traveling rule is the fact that there is an item for each function. So I do not see regular sponges in the possession of my cleaners -- sa kitchen sinks lang meron.
Cleaners/helpers are like small kids.
Give them enough supply to work with; give them a simple variety with a simple correlation -- okay na.
I sell to the cleaners the idea that the sponge alternative/type of sponge -- if used for a certain place/item is going to make the work easy for them. Happy ako and they will not have to do it all over again.
I even say -- tatagal ang manicure mo. LOL
I do not bother to convince them on the necessity of preventing cross-contamination (which is the underlying logic behind it all). LOL
And yes -- pictures of the sponge and the sponge-alternatives together with the surfaces they are used for is in the manual of my cleaners.
It is part of my training "module" -- LOL. (Ako nga yung amo na ayaw makiusap masyado with househelp.

After 2 or 3 bantays with minimal instructions -- and sporadic checks, the cleaners just decide to do it my way.)
This morning, I decided to do a top to bottom ocular inspection of my house -- more closely than my 15-min daily breeze through before I go off to the office. Happy ako coz everything is clean and in order, as I want it to be 24/7.