I love those foaming soap pumps, but I saw several problems after I refilled them a couple of times.

The pump clogs
The top sticks in the down position
The foam spurts out in a loose, wet consistency that is half stream and half froth

I can buy disposable foaming soap (think "Dial" or "Softsoap") for about $3, or I can buy empty refillable bottles (think "Oxo" or "mDesign") for about $10.

I've seen lots of guides that simply tell you to run water through it and re-use, tada! Errrr, no. Anyone who's trying to fix one of these has already done this. I've taken apart many of these, and I finally got it down from one end to the other.

Step 1: Anatomy of a Foam Pump Top

Here are the guts of a pump top, clockwise from left.

Soap straw
Pump spring
Plunger
Pump nozzle
Screw-on bottle closure
Foam mixing chamber
Gasket for screw-on bottle closure
Bead stopper for soap liquid

Step 2: How the Guts Come Apart (and Fit Together)

Be careful when you pull the pump top apart. It's all held together with friction, so pull firmly with steady pressure.

Work over a clean empty sink, over a sieve and close the drain. The little round bead is essential and will definitely drop into the sink and be lost to the drain forever. Game over.

Here's how the bead sits, inside the mixing chamber, and against the end of the spring, as shown in both the exploded view and the in-use view. You won't be able to reach the column where the bead goes. You may have to line it up and drop it in a few times, but you'll get it. If it's dry you can try a piece of tape, lower it into position, and scrub the bead off so it will drop into position.

Step 3: The Pesky Bead

I have lost the bead (read previous step "lost to the drain. Game over").

I have also gotten very lucky to find a round-headed pin in my sewing materials whose top fit perfectly when snipped off the pin. If the pump sticks in the down position, clean all the pieces well. It's not likely that the spring has worn out, it's that something is causing friction or adhesion. Get it all pulled apart and clean all surfaces until clean as new.

Step 4: Clogs and Lack of Foam

Here's where you will see most clogs and poor foam consistency.

It took me awhile to realize there is a cylinder that hides inside the pump top, and holds the answer to how the foam is made. See it deep inside the pump top? You may have to coax it out gently with a pin (grab the edge and pry it out), tweezers, or forceps. Once you get it out, note that there are 2 mesh surfaces, one on each end of the cylinder.

Step 5:

I've seen 2 problems here at the cylinder. One or both mesh ends can get clogged with soap globs or contaminants. Just wash it clean gently with warm water and a toothbrush.

The other problem is when one or both mesh ends are torn. The plastic mesh is fused on with heat, but we don't need heat to do the repair. Find some sheer fabric curtains at the thrift store. It's polyester and comes in all sorts of colors, usually costing less than $5 per pair. Here I'm using pink.

Step 6: Replacing the Mesh

Cut a postage-stamp sized piece of the curtain sheer. I like to run a lighter flame across the edges so it doesn't fray, but it's not really necessary. If you do this make sure you are very careful and take precautions such a working over a sink away from anything flammable.

When it's ready, stick the mesh on the end(s) needed and push the cylinder back into position. It goes in large end first. It's hard to make the mesh stay wrapped around the cylinder end on the smaller outer end. Fortunately, this is not necessary. You can just slap it over the opening and it will push into place when you put all the pieces back together.

Step 7: Reassemble

If you forgot how the pieces go, here's your cheatsheet.

Soap straw
Pump spring
Plunger
Pump nozzle
Screw-on bottle closure
Foam mixing chamber
Gasket for screw-on bottle closure
Bead stopper for soap liquid

Insert the straw (1) into the bottom of the mixing champber (6). Put the gasket (7) on top of the bottle opening and insert the foam mixing chamber (6) into the bottle so that it sits on the gasket (7). Drop the bead (8) into the center the mixing chamber (6). Insert the pump spring (2) behind the bead (8). Add the plunger (3) cup side down to the top of the spring (2). On top of all this, add the bottle closure (5). And finally, on top of all this, add the nozzle (4).