I bought 4 squashy light up balls through Campus Gifts and one burst after only 15 minutes of use by a nine year old who did not put the ball under excessive pressure. Thankfully there were adults around when the ball burst onto the child's foot and the carpet. We can only be grateful that the contents of the ball didn't burst into the child's face and eyes. The supplier and manufacturer say that the balls are safe but we are not convinced. We are also told that the contents won't stain the carpet, which is not the case. We are still trying to remove the gluey contents of the ball from the carpet. Campus Gifts has offered to refund the purchase price and P&P but will not pay for the carpet to be professionally cleaned. We think these squashy light up stress balls should carry a conspicuous warning that they can burst or leak. Either that, or withdraw them from the market.