Examine the marionette puppet closely. The most common repair of a marionette puppet is a string replacement. While replacing the string, go ahead and check for paint wear and joint damage.
Repair paper mache with a quality paper mache. Be sure to use small enough strips to follow the small contours of the puppet's features. You can obtain this from your local artist supply store. If your marionette is made out of wood, continue to Step 3.
Paint all worn pieces with good quality paint, being careful not to paint any black strings attached to the arms, legs and head of the marionette puppet. Let the puppet dry completely before attempting any further repairs.
Replace or repair all broken joints of the arms, legs and neck of the marionette puppet. You may need to use new joint hardware if the metal is corroded or damaged. Use needle nose pliers to get into tight spaces.
Re-string the strings that are broken or loose with 25 lb. black marionette string. Make sure no strings are tangled or wrapped around an arm or leg and be sure that each string goes to the proper place on the "T."