Use a soft cloth with a little alcohol and gently wipe along the edge of the welding bar to clean off any plastic residue. Do not use anything abrasive as it can damage the welding bar and prevent the machine from cutting properly.
If you are trying to cut the cover and it's being pulled there might be plastic residue on the roller. You can turn the machine over carefully and try to clean the roller using a soft cloth with alcohol to remove plastic residue. If this doesn't fix the problem call our service department.
That depends on the use of the books. Generally the 3.5 mil thickness will last 2-3 years under normal conditions. The 4.7 mil covers can last 3-5 years. Like anything covers can be abused and might have to be replaced sooner.
Absolutely not! The CoLibri covers are acid free and have no harsh or toxic chemicals. They do not stick to the books. The covers can be removed anytime and replaced with a new cover without any damage to the book. Unlike other brands there is no need for adhesives or tape and the covers do not stick to the book.