Advanced Leather Repair

Cracks in Leather
The only way to un-crack leather is to replace it. One approach that leather repair specialists use is to clean the leather and then re-color it. The result is that the leather will have a uniform appearance. The cracks will still be there but will be less apparent.
You can also have a leather repair professional replace the cracked areas and match the new leather to the original color. This works best when you are working with a panel of leather, for example on a car seat or the surface of a furniture cushion.
Dog and Cat Scratches
If you own a dog or cat, do not allow them on your leather furniture – PERIOD!
For dogs, most damage occurs while climbing on and jumping off. If you are a cat owner, leather fillers or tanner’s resin will cure the symptoms but not the problem.
You might consider buying your cat a scratching post and put it near the area where the cat is scratching before using the filler.
Spray water on the scratch and cover it with a small square of 1000 grit wet sand paper from the hardware store. Sand very lightly until the surface is smooth and you cannot feel the tear from the scratch anymore. You may end up needing to re-color the furniture if the scratch damage is extensive. That would be a job for a pro.
Leather Repair Kits
If your leather has a tiny tear and it's not highly visible, (and if the color is black) any leather repair kit should be sufficient if you follow directions.
However, there are a couple of things to be aware of in case you run into problems. The repair material may not bond well with the leather. This happens if the leather is old or if the heating element supplied with the kit (if it's included) is not hot enough.
Usually, a leather repair kit will contain grain papers that you rub over the repaired area to imprint a grain-like finish. The idea is that the grain will resemble that of the original undamaged leather as much as possible.
Some grain papers are also pigmented. It's difficult to match color but it's even more difficult if the leather is old. Experts say that unless the leather color is black, the repair will show.
You may need to place a small piece of cloth and padding under the tear to help hold the edges together. You can place a piece of material under the tear and glue it with the edges to be repaired as close together as possible. Hold the edges together while the adhesive dries, or use a hair dryer (very carefully) to speed up the process.
Using a leather repair kit will usually hide the tear and hopefully prevent further damage. The problem with using a leather repair kit is the damaged area will always be weaker. The other thing you can do of course is have someone replace the damaged section of leather and match the color professionally.
Stuck Leather
If you have a leather item with sides, such as a purse that appear to be stuck together, look inside to see if you can tell exactly where the sides are sticking. You should be able to see if it is sticking in a couple of places or if the leather is completely stuck shut.
Hold the item over a pot of boiling water – not too closely and do not allow the purse to get soaked. The heat and humidity will expand the pores in the leather and might allow you to work the sides free, just do not force them if they will not budge.
You could also try to work some leather cleaner in between the sides. If there is dirt or other grime that's holding the sides together, this may loosen it. Finally, if getting the sides separated doesn't look easy, take it to a cobbler for repair.
Specialized Leather Repair
http://www.ADVLeather.com
Offers a specialized leather repair service and professional training. They'll bend over backwards to help you clean or repair a leather item yourself.
They also offer private tutoring to teach you the finer points of premium leather repair. If you are looking for a career change, you could build a respectable leather repair business by taking the course they offer.