I have bar chart, with a lot of custom properties ( label, linewidth, edgecolor)
import matplotlib.pyplot as plt
fig = plt.figure()
ax = plt.gca()
x = np.a
In your case, bars is only a BarContainer, which is basically a list of Rectangle patches. To just remove those while keeping all other properties of ax, you can loop over the bars container and call remove on all its entries or as ImportanceOfBeingErnest pointed out simply remove the full container:
import numpy as np
import matplotlib.pyplot as plt
fig = plt.figure()
ax = plt.gca()
x = np.arange(5)
y = np.random.rand(5)
bars = ax.bar(x, y, color='grey', linewidth=4.0)
bars.remove()
x2 = np.arange(10)
y2 = np.random.rand(10)
ax.bar(x2,y2)
plt.show()