who can tell me the difference between liquin and maroger medium?

"Liquin" is the brand name of an oil/alkyd/solvent painting medium from Winsor & Newton. It comes in various viscosities and improves the drying rate of oil paints.

"Maroger's medium" is an early 20th C reincarnation of the notorious and universally denigrated "megilp," a concoction of various ingredients intended in the 18th and 19th C to simulate the "golden glow" of Old Master paintings. It yellows, turns brown, and cracks with age.

Jacques Maroger was a "restorer" at the Louvre Museum in Paris. He reinvented megilp.

If maroger cracks and turns yellow, how is it that we have so many wonderful old master's paintings still fresh and magnificent?