Better way to mute fundamental baseband frequency?
Use a notch filter such as the one shown in the figure below, where $\omega_n =2\pi 60/f_s$, where $f_s$ is your sampling rate, and $\alpha$ is chosen based on the bandwidth of the notch and how long you can allow for settling in the time domain; the tighter the filter bandwidth the longer it will take to settle; you can use a first order approximation of 10%/90% rise time = $\frac{0.35}{BW}$ where the BW is in Hz (and the amount of precision you can allow in the filter is an important factor---insufficient precision and $\alpha$ to close to 1 can lead to instability). 





See this post for details: Transfer function of second order notch filter

Note the diagram below to facilitate implementation, mapping the coefficients to the transfer function as commonly referenced in Matlab and Octave. Do note that the signal flow below is going from right to left, which is opposite the diagram above (this was because my slide was showing how the implementation came from transposing the Direct Form II implementation). To be clear, the resulting coefficients are:

$b_0 = 1$

$b_1 = -2cos(\omega_n)$

$b_2 = 1$

$a_1 = -2\alpha cos(\omega_n)$

$a_2 = -\alpha^2$

A normalizing gain of $(1+\alpha)/2$ is added to the whole filter. Since $\alpha$ is typically close to 1, this can reasonably be omitted in most cases.