Yes, the 1-piece "White Tombac" buttons area lot more brittle than brass ones, tending to crack like a pottery dinnerplate. I should also explain, many people call those those silvery-grey-metal buttons "tombac" but actual tombac is an orangish-golden variety of brass, containing about 10% more copper than yellow brass contains. Canada made some 5-cent coins out of tombac during World War Two, and uncirculated ones are the orangish-golden color I mentioned. "White Tombac" is regular tombac with a small amount of Arsenic added to the molten brass alloy, which turns the metal to a silvery-grey color. Anybody who wants to learn more can do a google search for tombac and "White Tombac".