Why do my games occasionally play in black-and-white instead of color?

Color cuts in and out sporadically. I haven't been able to discern the cause of this problem as of yet. SNES is situated on a plastic box of sorts on my basement floor. Sometimes stomping on the basement floor either will restore full color or switch it back to black and white. I do not have the necessary tool to open my SNES as it is only available online and I am without either a credit or debit card (why is this tool not sold at brick-and-mortar stores such as Home Depot, Gamestop, etc.???). This is a recent problem I have been experiencing (as of 2017). It is both confusing and frustrating so, any help would be greatly appreciated. Please inform me if there is any easy way to rectify this situation. Thank you!!!